Jeff Plow Manual

Fisher EngineeringJuly 2001

Lit No. 27179

MECHANIC'S GUIDEMECHANIC'S GUIDEMECHANIC'S GUIDEMECHANIC'S GUIDEMECHANIC'S GUIDE

SNOSNOSNOSNOSNOWPLWPLWPLWPLWPLOOOOOWSWSWSWSWS

Featuring theInsta-ActInsta-ActInsta-ActInsta-ActInsta-Act®®®®® Hy Hy Hy Hy Hydrdrdrdrdraulic Systemaulic Systemaulic Systemaulic Systemaulic System

and theE-FE-FE-FE-FE-Forororororce Isolace Isolace Isolace Isolace Isolation Module Systemtion Module Systemtion Module Systemtion Module Systemtion Module System

S Y S T E M®

CAUTIONRead this manual before servicing the snowplow.

Lit. No. 27179 3 July 2001

PREFACE

Service of your FISHER snowplowequipment is best performed by yourlocal FISHER outlet. They know yoursnowplow best and are interested inyour complete satisfaction.

TABLE OF CONTENTS

Preface ............................................................................................................ 3Safety Information .......................................................................................... 4Product Specifications ................................................................................... 6Required Tools ................................................................................................ 6Hydraulic Hose Routing ................................................................................. 7Hydraulic Unit Parts Diagram ........................................................................ 8Solenoid Cartridge Valve Identification and Location ................................ 9Relief Valve Identification and Location .................................................... 10Pilot-Operated Check Valve Identification and Location .......................... 11Vehicle Harness and Vehicle Cable Location ............................................ 12Operating the Snowplow ............................................................................. 13Theory of Operation ..................................................................................... 15Hydraulic and Electrical Schematics .......................................................... 17 Electrical Schematic .......................................................................... 18 Hydraulic Schematic ......................................................................... 19 Raise ................................................................................................... 20 Lower .................................................................................................. 22 Angle Right ......................................................................................... 24 Angle Left ........................................................................................... 26 Hold in Raise Position – Hydraulic ................................................... 28 Striking an Object While Plowing – Left Cylinder Retracts ........... 29 Striking An Object While Plowing – Right Cylinder Retracts ......... 30 High Beam Headlamps With Snowplow Connected to Vehicle .... 31 Low Beam Headlamps With Snowplow Connected to Vehicle ..... 32Troubleshooting Guide................................................................................. 33Removable Spring Tool ............................................................................... 67

This guide has been prepared to helpthe trained mechanic service FISHER®

snowplows. It also provides safetyinformation and recommendations.We urge all mechanics to read thismanual carefully before attempting toservice the FISHER snowplowequipment covered by this guide.

Lit. No. 27179 4 July 2001

CAUTIONIndicates a situation that, if notavoided, could result in minorpersonal injury and/or damageto product or property.

NOTE: Identifies tips, helpful hintsand maintenance information theowner/operator should know.

WARNINGIndicates a potentiallyhazardous situation that, if notavoided, could result in deathor serious personal injury.

SAFETY INFORMATION

Instruction Label

Warning Label

Please become familiar with and make ownersknowledgeable of the Warning and Instruction labels

on the back of the blade!

WARNING

CAUTION

LOWER BLADE WHEN VEHICLE IS PARKED.

REMOVE BLADE ASSEMBLY BEFORE PLACING VEHICLEON HOIST.

DO NOT EXCEED GVWR OR GAWR INCLUDING BLADEAND BALLAST.

READ OWNER'S MANUAL BEFORE OPERATING ORSERVICING SNOWPLOW.

TRANSPORT SPEED SHOULD NOT EXCEED 45 MPH.REDUCE SPEED UNDER ADVERSE TRAVELCONDITIONS.

PLOWING SPEED SHOULD NOT EXCEED 10 MPH.

REMOVE SLACK FROM CARRYING CHAIN BEFORETRAVELING.

SEE YOUR FISHER OUTLET FOR APPLICATIONRECOMMENDATIONS.

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Warning Label

Instruction Label

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WARNINGLower blade when vehicle isparked. Temperature changescould change hydraulicpressure, causing the blade todrop unexpectedly ordamaging hydrauliccomponents. Failure to do thiscan result in serious personalinjury.

BEFORE YOU BEGIN

Lit. No. 27179 5 July 2001

WARNINGDo not exceed GVWR or GAWRincluding blade and ballast.The rating label is found on thedriver-side vehicle doorcornerpost.

• Park the vehicle on a level surface,place shift lever in PARK orNEUTRAL and set parking brake.

• Leave the snowplow mounted onthe vehicle and lowered for mostservice procedures, unless toldotherwise.

PERSONAL SAFETY

• Wear only snug-fitting clothingwhile working on your vehicle orsnowplow.

• Do not wear jewelry or a necktie,and secure long hair.

• Be especially careful near movingparts such as fan blades, pulleysand belts.

VENTILATION

If you work on the vehicle or snowplowin a garage or other enclosed area, besure to vent exhaust gas directly tothe outside through a leakproofexhaust hose.

WARNINGHydraulic oil under pressurecould cause skin injectioninjury. If you are injured byhydraulic oil, get medicalattention immediately.

HYDRAULIC SAFETY

SAFETY INFORMATION

WARNINGVehicle exhaust containsdeadly carbon monoxide (CO)gas. Breathing this gas, evenin low concentrations, couldcause death. Never operate avehicle in an enclosed areawithout venting exhaust to theoutside.

BEFORE YOU BEGIN

WARNINGRemove blade assembly beforeplacing vehicle on hoist.

• If you suspect a hose leak, DONOT use your hand to locate it.Use a piece of cardboard or wood.

• Always loosen plugs, fittings andvalves slowly to bleed off anyresidual pressure.

CAUTIONBatteries normally produceexplosive gases which cancause personal injury.Therefore, do not allowflames, sparks or lit tobacco tocome near the battery. Whencharging or working near abattery, always cover your faceand protect your eyes, andalso provide ventilation.

Batteries contain sulfuric acidwhich burns skin, eyes andclothing.

Disconnect the battery beforeremoving or replacing anyelectrical components.

BATTERY SAFETY

FIRE AND EXPLOSION

• Wear safety goggles to protectyour eyes from battery acid,gasoline, dirt and dust.

• Avoid touching hot surfaces suchas the engine, radiator, hoses andexhaust pipes.

• Always have a fire extinguisherhandy, rated BC for flammableliquids and electrical fires.

Be careful when using gasoline. Donot use gasoline to clean parts. Storeonly in approved containers away fromsources of heat or flame.

WARNINGGasoline is highly flammableand gasoline vapor isexplosive. Never smoke whileworking on vehicle. Keep allopen flames away fromgasoline tank and lines. Wipeup any spilled gasolineimmediately.

• Always inspect hydrauliccomponents and hoses beforeusing. Replace any damaged orworn parts immediately.

Lit. No. 27179 6 July 2001

PRODUCT SPECIFICATIONS

Electrical System –approximate values:

• Solenoid Coil Resistance =7 Ohms at room temperature

• Solenoid Coil Amp. Draw =1.5 Amp.

• Motor Relay Coil Resistance = 16- 17 Ohms

• Motor Relay Amp. Draw =0.7 Amp.

• Motor Amp. Draw = 190 Amp. at1750 psi

• Switched Accessory Lead Draw =0.75 Amp

Vehicle Control Harness Fuse Size

• Park/Turn – 15 Amp. (ATC)• Control – 7.5 Amp. (ATC)

REQUIRED TOOLS

Mechanical

Fastener Torque in IN–LBPump Cap Screws ............................ 150 – 160Motor Terminal Nuts.......................... 50 – 60Motor to Manifold Cap Screws .......... 30 – 40Reservoir Screws .............................. 15 – 20Valve Cartridges................................ 115 – 125Coil Nuts ........................................... 48 – 60Cartridge / Coil Cover Screws........... 15 – 20Check Valve...................................... 115 – 125

Hydraulic Oil

• FISHER® High Performance Fluidto -25°F (-32°C)

Fluid Capacity—Hydraulic Oil• Unit Reservoir = 1-1/2 Quarts• System Total = 2-1/4 Quarts

Solenoid Valve Spool Travel =0.07" for three- and four-way valves(S2, S3) . Travel of two-way valve (S1)spool is not detectable with voltageapplied to coil.

CAUTIONDo not mix different types ofhydraulic fluid. Some fluidsare not compatible and maycause performance problemsand product damage.

Insta- Act® Hydraulic System Tools Required to service theelectrical and hydraulicsystems:

• Long Slender Needle Nose Pliers• Flat Screwdriver• Sockets and Combination

Wrenches: 3/8" thru 7/8", 1-1/16",1-1/8"

• Deep Socket: 7/8"• 1/4" Socket or Nut Driver• 12 V Test Light• Torque Wrench (in-lb)• Allen Wrench Set• 3000 PSI Pressure Gauge

w/adapter fittings• Flashlight• Pick Set• Hammer• Digital Volt/Ohm Meter• Pencil Magnet• T-20 Torx

Available from your FISHER® outlet:• Minute Mount® Electrical Tester• Isolation Module Tester• Removable Spring Tool

(for replacing trip springs)• Hydraulic Pressure Test Kit

(Available late 2001)

Lit. No. 27179 7 July 2001

HYDRAULIC HOSE ROUTING

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HYDRAULIC UNIT PARTS DIAGRAM

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Lit. No. 27179 9 July 2001

SOLENOID CARTRIDGE VALVE IDENTIFICATION AND LOCATION

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Lit. No. 27179 10 July 2001

RELIEF VALVE IDENTIFICATION AND LOCATION

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Lit. No. 27179 11 July 2001

PILOT-OPERATED (POPPET TYPE) CHECK VALVE IDENTIFICATION AND LOCATION

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Lit. No. 27179 12 July 2001

VEHICLE HARNESS AND VEHICLE CABLE LOCATION

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Lit. No. 27179 13 July 2001

OPERATING THE SNOWPLOW

Solenoid Control

Turn the vehicle ignition switch on. Turn the control on. The control indicator light should be on.

Action Description of OperationON/OFF Slide the control power switch to ON to activate the hydraulic system. Turn the control OFF to lock the

blade in place. This prevents accidental movement of the blade.Raise Move the control lever up (forward) to raise the blade to the desired height.Lower/Float Move the control lever down (back) to lower the blade and activate the FLOAT mode.Right Move the control lever right to angle the blade to the right.Left Move the control lever left to angle the blade to the left.CancelFloat

Cancel the FLOAT mode by momentarily placing the control in the RAISE position, turning the controloff, or turning the vehicle ignition off. Angling left or right does not cancel float.

Mount the blade and attachments tothe vehicle. Make the three electricalconnections. Turn the vehicle ignitionswitch to the ON or the ACCESSORYposition. Move control ON/OFFswitch to the ON position. The controlindicator light (red) should lightwhenever the control ON/OFF switchand the ignition (key) are both turnedON.

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CAUTIONTo prevent accidentalmovement of the blade,always turn the ON/OFF switchto OFF whenever thesnowplow is not in use. Thecontrol indicator light will turnoff.

CAUTIONDO NOT hold control lever inRAISE, ANGLE LEFT or ANGLERIGHT position after blade hasreached desired position. Todo so could result in thehydraulic fluid overheating.

WARNINGThe driver shall keepbystanders clear of the bladewhen it is being raised,lowered or angled. Do notstand between the vehicle andthe blade, or within 8 feet of amoving blade. A moving orfalling blade could causepersonal injury.

Lit. No. 27179 14 July 2001

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2. Press the ON/OFF button on thecontrol. The control indicator lightglows red indicating the control ison. The control indicator lightglows red whenever the controlON/OFF switch and the vehicleignition switch are both ON.

3. Press the LOWER button for 0.75seconds to engage the FLOATmode. The control indicatorFLOAT light glows green. Cancelthe FLOAT mode by momentarilypressing the RAISE button.

Function Time Outs

All control functions, except forLOWER, automatically time out—stop—after a period of time. Thishelps prolong the battery charge. Thetime-out period for the RAISE functionis 4.8 seconds, while the anglefunction is 9.6 seconds.

The control automatically turns offafter being idle for 20 minutes.

Smooth StopThe control automatically allows theblade to coast to a stop. This resultsin smoother operation, reduces theshock to the hydraulic system andincreases hose and valve life.

Fish-Stik® Hand-Held Control

OPERATING THE SNOWPLOW

1. Turn the vehicle ignition switch tothe ON or the ACCESSORYposition. The control logo areailluminates.

Button Description of OperationRaise Press this button to raise the snowplow and to cancel the float mode.

NOTE: Snowplow automatically stops raising after 4.8 seconds. To resume raising the snowplow,release the button and press again.

Lower/Float

Press this button to lower the snowplow. NOTE: After reaching the desired height, release the button.Holding the button down for more than 0.75 seconds activates the float mode, indicated by greenFLOAT lamp.

Right Press this button to angle blade to the right.Left Press this button to angle blade to the left.CancelFloat

Cancel the float mode by momentarily pressing and releasing the RAISE button, turning control off, orturning vehicle ignition off. Angling left or right momentarily cancels float.

CAUTIONTo prevent accidentalmovement of the blade,always turn the ON/OFF switchto OFF whenever thesnowplow is not in use. Thecontrol indicator light will turnoff.

WARNING

The driver shall keepbystanders clear of the bladewhen it is being raised,lowered or angled. Do notstand between the vehicle andthe blade, or within 8 feet of amoving blade. A moving orfalling blade could causepersonal injury.

Lit. No. 27179 15 July 2001

THEORY OF OPERATION

Snowplow Headlamps

The Isolation Module acts as anelectrical hub, automatically directingvehicle power to the appropriatevehicle or snowplow lighting devices,while also supplying battery power tothe snowplow control.

The vehicle high and low beams enterand exit the Isolation Module throughpositions 3 (left side lighting) andposition 4 (right side lighting). Park,turn, and DRL signals also enterthrough positions 3 and 4.

The output of the vehicle dimmerswitch is directed to the IsolationModule via the long and short plug-inharnesses. When the snowplow is notattached to the vehicle, the signalpasses through the normally closedrelay contacts to the vehicleheadlamps. During this time, theIsolation Module is inactive, placing nocurrent draw on the vehicle's electricalsystem.

With the snowplow attached, theIsolation Module is still inactive untileither of the two following conditionsare met: the vehicle parking lights areturned on or the vehicle ignition switchis turned on.

Snowplow Daytime RunningLamps

Because Daytime Running Lamps(DRLs) are controlled differently onsome vehicles, two Isolation Moduleshave been developed.

The standard Isolation Moduletransfers the DRL output from thevehicle headlamps to the snowplowlights when the vehicle ignition switchis on and the snowplow is attached.

The Isolation Module designed for the1999-20_ GMC All New Sierra and1999-20_ Chevy Silverado senses thevehicle in the DRL mode. A series ofrelays energize, placing the snowplowheadlamps in the DRL mode. ThisIsolation Module does not turn off thededicated vehicle DRLs.

Turning on the vehicle parking lightsactivates a series of relays,automatically transferring the vehiclehigh and low beams to the snowplowwhile supplying battery power directlyto the snowplow parking lights. Allsnowplow lighting exits the IsolationModule through position 2.

Turning on the vehicle ignition switchenergizes a snowplow control relay,supplying vehicle battery powerdirectly to the control via the vehiclecontrol harness. The vehicle ignitionswitch also supplies power to thevehicle turn signals. Activating thevehicle turn signals energizes turnsignal relays, which supply vehiclebattery power directly to the snowplowturn signals.

Lit. No. 27179 16 July 2001

The snowplow hydraulic systemperforms four blade movements:RAISE, LOWER, ANGLE RIGHT, ANDANGLE LEFT.

All four movements require the vehicleignition (key) switch to be in the run oraccessory position and the cabcontrol to be turned on.

Snowplow Hydraulics

Three hydraulic movements requireenergizing the electric motor, shiftingsolenoid cartridge valve(s) or activatingcheck valves. The fourth function,LOWER, does not energize the motorbut shifts a solenoid cartridge valve.

THEORY OF OPERATION

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Power to the three solenoid cartridgevalves is supplied by the vehiclebattery, via the Isolation Module andcab control. The three solenoidcartridge valves operate in variouscombinations, electrically activated bythe cab control, to send hydraulic fluidto the snowplow lift and anglecylinders or back to the reservoir.

Lit. No. 27179 17 July 2001

HYDRAULIC AND ELECTRICAL SCHEMATICS

This section contains hydraulic andelectrical schematics to help explainhow the hydraulic unit performs thedifferent functions. A schematic is anabstract drawing showing the purposeof each component in the system.Each component is represented by agraphical symbol. The hydraulic andelectrical legends describe eachsymbol used in the schematics forthis guide.

The first two schematics show anoverview of the complete hydraulic andelectrical systems. Other schematicshighlight the flow of hydraulic oil andelectrical current for each function thehydraulic unit performs as well as theflow of electrical current for thesnowplow and vehicle lights.

• Bold lines and gray lines (ground)represent the circuit beingactivated only.

• Shaded components are eitheractivated or shifted from theirnormal position.

Wire Color Code AbbreviationsBLK Black BLU/ORN Blue w/ Orange GRY Gray PUR Purple DRL Daytime Running LampsBLK/ORN Black w/ Orange BRN Brown LTBLU Light Blue RED Red MTR RLY Motor RelayBLK/RED Black w/ Red BRN/GRN Brown w/ Green LTGRN Light Green WHT White P/T SIG Park / Turn SignalBLK/WHT Black w/ White BRN/RED Brown w/ Red ORN Orange WHT/YEL White w/ YellowBLU Blue GRN Green PNK Pink YEL Yellow

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Lit. No. 27179 18 July 2001

ELECTRICAL SCHEMATIC

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RAISE – ELECTRICAL

Blade Movement: Raise

Control: Raise

System Response:

1) By moving control lever or pressingthe control button, the circuitboard within the cab controlswitches power to the electricalcircuits.

2) Motor relay closes, current flowsthrough the motor relay, activatingthe pump motor. +12V is appliedto the coil of solenoid cartridgevalve S3, shifting the spool.

3) Hydraulic oil from the pump flowsthrough solenoid cartridge valvesS3 & S2, through the internalcheck valve in solenoid cartridgevalve S1 into the base end of thelift cylinder causing it to extend.

Lit. No. 27179 21 July 2001

RAISE – HYDRAULIC

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LOWER – ELECTRICAL

Blade Movement: Lower / Float

Control: Lower

System Response:


2) +12V is applied to the coil ofsolenoid cartridge valve S1,shifting the spool.

3) The weight of the plow forces thelift cylinder to retract. Theretracting lift cylinder pushes thehydraulic oil out of its base end,through solenoid cartridge valvesS1 & S2 & S3, and back to thereservoir.

NOTE: Angling left or right usingthe Fish-Stik® handheld controlmomentarily cancels Float whilethe button is depressed. Float isnot cancelled by angling whenusing the solenoid control.

Lit. No. 27179 23 July 2001

LOWER – HYDRAULIC

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Blade Movement: Angle Right

Control: Right

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2) Motor relay closes, current flowsthrough the motor relay, activatingthe pump motor. +12V is appliedto the coil of solenoid cartridgevalve S2, shifting its spool.

3) Hydraulic oil from the pump flowsthrough solenoid cartridge valveS3, P/O check valve and into thebase end of the left cylindercausing it to extend.

4) The retracting right cylinderpushes the hydraulic oil out of itsbase end, through solenoidcartridge valves S2 & S3 back tothe reservoir.

Lit. No. 27179 25 July 2001

ANGLE RIGHT – HYDRAULIC

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Blade Movement: Angle Left

Control: Left

System Response:


2) Motor relay closes, current flowsthrough the motor relay, activatingthe pump motor. +12V is appliedto the coil of solenoid cartridgevalves S2 & S3, shifting bothspools.

3) Hydraulic oil from the pump flowsthrough solenoid cartridge valvesS3 & S2 and into the base end ofthe right cylinder causing it toextend.

4) Pressure within the hydrauliccircuit causes the P/O check valveto open.

5) The retracting left cylinder pushesthe hydraulic oil out of its baseend, through the open P/O checkvalve and solenoid cartridge valveS3 and back to the reservoir.

Lit. No. 27179 27 July 2001

ANGLE LEFT – HYDRAULIC

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Lit. No. 27179 28 July 2001

HOLD IN RAISE POSITION – HYDRAULIC

1) Hydraulic oil is trapped in the baseend of the lift cylinder by theinternal check valve in solenoidcartridge valve S1.

2) When the snowplow contacts anobject, the force of the impactincreases the hydraulic pressurein the base end of the cylinder.When the pressure exceeds therelief valve pressure setting, therelief valve opens allowing oil toflow to the base of the oppositecylinder.

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System Response:

Striking an Object While Plowing

Lit. No. 27179 29 July 2001

STRIKING AN OBJECT WHILE PLOWING – LEFT HYDRAULIC CYLINDER RETRACTS

1) Hydraulic oil is trapped in the baseend of the cylinders by the reliefvalves, the P/O check valve andsolenoid cartridge valve S2.


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Lit. No. 27179 30 July 2001

STRIKING AN OBJECT WHILE PLOWING – RIGHT HYDRAULIC CYLINDER RETRACTS

Control: None

System Response:

1) Hydraulic oil is trapped in the baseend of the cylinders by the reliefvalves, the P/O check valve andsolenoid cartridge valve S2.


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Lit. No. 27179 31 July 2001

HIGH BEAM HEADLAMPS WITH PLOW CONNECTED TO VEHICLE

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LOW BEAM HEADLAMPS WITH PLOW CONNECTED TO VEHICLE

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Lit. No. 27179 33 July 2001

TROUBLESHOOTING GUIDE

Troubleshooting GuideContents

General Diagnostic Table .......... 34Packing Nut Adjustment ............. 37Motor Test .................................... 38Motor and Motor Relay TestDiagram ....................................... 39Motor Relay Test ......................... 40Vehicle Control Harness Test ..... 41Control Test ................................. 43Pump Pressure Test .................... 44Cartridge Coil Activation Test .... 45Hydraulic System Test ................ 46Relief Valve Inspection andAdjustment .................................. 47Pilot-Operated Check ValveInspection .................................... 48Individual Solenoid Coil Test .... 49Solenoid Cartridge ValveInspection .................................... 49Vehicle Headlamp Test .............. 50Snowplow Headlamp Test ......... 54Vehicle Daytime RunningLamps Test .................................. 65Snowplow Daytime RunningLamps Test .................................. 66

How to Use theTroubleshooting Guide

Introduction

This guide consists of a series oftables, diagrams, flowcharts and otherinformation. When used properly ithelps the mechanic to identify andrepair faulty system components.Fisher Engineering recommends usingthe Electrical Tester as a timesavingtool for electrical system diagnosis.When using this tester, refer to thesupplied instruction manual.

All malfunctions of the snowplow canbe categorized as mechanical,electrical, or hydraulic. Mechanicalissues are generally related to theblade or attachments and can usuallybe identified by visual inspection.However, electrical and hydraulicissues can be difficult to trace to thecomponent level and that is thepurpose of this troubleshooting guide.

When diagnosing the snowplowelectrical and hydraulic systems,some conditions must be eliminatedin order to develop valid tests. Theseconditions are listed before the tablesor flowcharts and must be satisfiedbefore proceeding.

If the listed conditions are not met,the procedure can result in inaccurateresults and wasted time.

In many cases, satisfying the listedconditions alone solves the problem.

1. Go to the General DiagnosticTable and satisfy the nine listedconditions. These conditionsmust be met before proceedinginto the table or to any subsequenttest.

2. Locate the condition in the tablewhich best describes the problemand check possible causes andactions in the order listed.

3. Proceed to a service procedure,another condition, or a specifictest as directed. All tests exceptthe Hydraulic System Test use a

flowchart format. To use theseflowcharts, first satisfy any listedconditions at the top of the page.Then begin at the upper left squareand proceed as directed.

4. Follow along sequentially throughthe table and tests, referring to thehydraulic and electricalschematics in the Theory ofOperation section and thecomponent Identification andLocation diagrams. Eventually theproblem is identified at thecomponent level.

Electrical Testing

Read and understand the Theory ofOperation section. A simple 12V testlight with a ground lead can be usedfor circuit testing. When directed tocheck for 12 volts (12V), ground thetest lamp lead and probe the terminal.When asked to check for ground,attach the test lamp lead to +12V andprobe the terminal. Note that 12V is anominal value. If using a voltmeter,actual voltage will vary with the vehicleand the presence of loads in testedcircuits. Continuity alone does notguarantee a good circuit. Poorconnectors or damaged wires mayhave continuity but be unable to carrysufficient current.

Read and understand the Theoryof Operation before attemptingtroubleshooting.

Lit. No. 27179 34 July 2001

GENERAL DIAGNOSTIC TABLE

BEFORE USING THIS GENERAL DIAGNOSTIC TABLE, OR PERFORMING ANY TESTS, YOU MUST VERIFY THE FOLLOWINGCONDITIONS:

1. Snowplow is attached to vehicleand all harnesses are connected.

2. Harness connector pins andterminals are free of corrosion,ensuring good connections, andcoated with dielectric grease.

3. Vehicle battery and chargingsystem are in good condition andbattery connections are clean andtight.

4. Hydraulic reservoir is filled to fillplug level with recommended fluidwhen lift cylinder is fully retracted.See Product Specifications.

5. No oil leaks from hoses, fittings,cylinders or the hydraulic unit.

6. All built up snow and ice isremoved from the snowplow.

7. FISHER® vehicle control harnessfuses are good.

8. Ignition is turned on or engine isrunning.

9. The control is connected in thecab and turned on.

CONDITION POSSIBLE CAUSE ACTIONMotor does not run for any requested function. Poor connection of vehicle’s or plow’s battery cable. Tighten and/or clean connections.

Motor relay inoperative. Go to Motor Relay Test.Defective control. Go to Control Test.Fault in vehicle control harness. Go to Vehicle Control Harness Test.Motor worn or damaged or pump seized. Go to Motor Test.

Motor runs continuously. Motor relay sticking or always energized. Go to Motor Relay Test.Defective control. Go to Control Test.Fault in vehicle control harness. Go to Vehicle Control Test.

Snowplow won’t raise—motor runs. Lift cylinder packing nut too tight. Adjust lift cylinder packing nut.Clogged pump filter (all functions are affected). * Clean or replace filter, flush reservoir.Worn or damaged pump. Go to Pump Pressure Test.* Thread sealant/tape is not compatible with hydraulics.

CAUTIONDo not mix different types ofhydraulic fluid. Some fluidsare not compatible and maycause performance problemsand product damage.

Lit. No. 27179 35 July 2001


CONDITION POSSIBLE CAUSE ACTIONSnowplow won’t raise—motor runs. Solenoid valve coils not energizing properly. Go to Cartridge Coil Activation Test.

Hydraulic system malfunction. * Go to Hydraulic System Test.Defective control. Go to Control Test.

Snowplow raises slowly or partially—motor runs. Poor connection of vehicle’s or plow’s cables. Clean and re-attach all connections.Clogged pump filter (all functions are affected). * Clean or replace filter, flush reservoir.Worn or damaged pump. Go to Pump Pressure Test.

Snowplow will not lower or lowers slowly, or won’t Lift cylinder packing nut too tight. Adjust lift cylinder packing nut.float. Solenoid valve coils not activating properly. Go to Cartridge Coil Activation Test.

Hydraulic system malfunction. * Go to Hydraulic System Test.Defective control. Go to Control Test.

Snowplow lowers by itself or won’t stay in raised Hydraulic system malfunction. * Go to Hydraulic System Test.position. Defective control. Go to Control Test.Blade will not hold angled position. Air in angle cylinders. Cycle angle functions to purge cylinders.

Oil bypassing crossover relief valve. Go to Relief Valve Inspection and Adjustment.Hydraulic system malfunction. * Go to Hydraulic System Test.

Snowplow does not perform the selected function orperforms a different function.

Hydraulic hose routing incorrect. Verify correct hose installation. See Hose RoutingDiagram.

Solenoid valve coils not energizing properly. Go to Cartridge Coil Activation Test.Hydraulic system malfunction. * Go to Hydraulic System Test.Defective control. Go to Control Test.* Thread sealant/tape is not compatible with hydraulics.

Lit. No. 27179 36 July 2001

CONDITION POSSIBLE CAUSE ACTIONFISHER® vehicle control harness control fuse blows. Red wire in vehicle harness is shorted to ground. Repair wire or replace vehicle harness.

Motor relay primary coil shorted internally. Check primary coil with ohmmeter. Replacedefective motor relay.

Solenoid valve coil shorted internally. Go to Individual Solenoid Coil Test. Replaceshorted coils.

Motor relay or solenoid coil wires in vehicle harnessshorted to ground.

Repair wire or replace vehicle harness.

Solenoid coil wires in snowplow harness shorted toground.

Repair wire or replace snowplow harness.

Defective control. Go to Control Test.Vehicle accessory fuse blows. Circuit overloaded. Consult vehicle owner’s manual for correct

application of aftermarket electrical loads.Excessive load on vehicle electrical system Pump Relief incorrectly adjusted. Go to Pump Pressure Test.while using snowplow. Worn or damaged motor or pump. Go to Pump Pressure Test.

Poor connection of battery cables. Inspect battery cables, clean and re-establish allbattery connections.

Snowplow headlamps operate irregularly or not at all Burned out bulbs or corroded sockets. Replace bulbs, clean contacts.–snowplow attached.

-or-Wires improperly located in connector inserted intoIsolation Module.

Review and correct wire installation.Go to Snowplow Headlamp Test.

Vehicle headlamps operate irregularly or not at all –snowplow removed.

Isolation Module improperly connected. Go to Isolation Module Test.

Vehicle daytime running lamps (DRLs) do not work. Parking brake on, vehicle not in drive. Lightsensor not deactivated.

Fully release parking brake, place vehicle in drive.Place light by sensor.

Power in DRL circuit has been interrupted. Turn lamp and/or ignition switch on and off to cyclethe DRL circuitry. Go to Vehicle DRL Test.

Snowplow DRLs do not work. Power in DRL circuit has been interrupted. Go to Snowplow DRL Test.Blade will not hold position. Hydraulic system malfunction. Go to Hydraulic System Test.


Lit. No. 27179 37 July 2001

ANGLE AND LIFT CYLINDERS

Cylinder with Packing Nut

If equipped with this type of cylinder,periodically verify the lift or anglecylinder packing nuts have notloosened. If a packing nut is loose orleakage appears when activating thecylinder, tighten the packing nut 1/4-turn after you feel the packing nutcontact the packing.

CAUTIONDo not overtighten the packingnut. Overtightening affects theoperation and life of thepacking.

If adjustment fails to stop fluid loss,replacement of packing and/or rod (ifthe chromed surface is pitted) may berequired.

NOTE: A small amount of leakageis acceptable to properly lubricatethe rod.

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Low Friction Cylinder

If equipped with this type of lift orangle cylinder, the gland nut istorqued to 150-180 ft-lbs at thefactory. Fluid leakage past the internalseal to the outside indicates a badseal and/or that chromed rod is pitted.Replacement of the damaged parts isrequired.

Lit. No. 27179 38 July 2001

MOTOR TEST

Refer to the Motor and Motor RelayTest Diagram. WARNING

The driver shall keepbystanders clear of the bladeduring this test. Do not standbetween the vehicle and theblade. A moving or fallingblade could cause personalinjury.

Refer to the Motor and Motor RelayTest Diagram.To activate the motor, the followingconditions must be met:

1. All three (3) snowplow and vehicleharnesses and cable assembliesmust be connected.

2. The vehicle control harness isplugged into position 1 of theIsolation Module.

3. The vehicle lighting harness isplugged into position 2 of theIsolation Module.

4. +12V from the battery must beconnected to one secondaryterminal of the motor relay.

5. The vehicle ignition switch must bein the ON position.

6. The control must be turned on.

MOTOR DOES NOT RUN

Connect the snowplowand vehicle harnessesand cable assemblies.

NONO

Correct themotor connections.

NO

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the motor relay?

Are snowplowand vehicle harnessesproperly connected?

YES Are motor connections correct(black/red stripe to positive terminal

and black to negative terminal)?

When the control is activated(raise, left, or right) is 12 volts on

the positive motor terminal?

Is the vehicle cableassembly black wire

connected to the negativebattery terminal?

Go to Motor Relay Test.

NO

YES

Connect to negativebattery terminal.

Check motor brushes,check for damaged or

seized pump.

NO

YES

NO

YES

MOTOR RUNS CONTINUOUSLY

Disconnect the brown/redstripe from the motor relay

primary terminal. Doesmotor stop?

Go to the Control Test.

Replace the motor relay.

YES

YES

Lit. No. 27179 39 July 2001

MOTOR AND MOTOR RELAY TEST DIAGRAM

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Lit. No. 27179 40 July 2001

NO

MOTOR RELAY TEST

1. Momentarily jump power andground directly from battery tomotor to verify that the motor runs.Make final connection at themotor.

2. Refer to the Motor and MotorRelay Test Diagram, and VehicleHarness and Vehicle CableLocation Diagram.

NOYES YES

Motor runs continuously

NO

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NO

Motor does not run

WARNINGThe driver shall keepbystanders clear of the bladeduring this test. Do not standbetween the vehicle and theblade. A moving or fallingblade could cause personalinjury.

Momentarily attach a jumpercable across the motor relay

secondary terminals.Does motor run?

Repair or replace red (+) cablefrom battery to motor relay.

Disconnect brown/red wirefrom motor relay primaryterminal. Does the motor

stop?

Replace motor relay.

Attach a jumper wire frombattery (+) to motor relay

primary terminal withbrown/red wire.

Does motor run?

Go to Vehicle Harness Test -Motor Relay. If OK, go to

Control Test.

Verify correct polarity ofcables from battery to

motor.

Go to Control Test.

Leave (+) jumper wire attachedand attach a ground jumper wirefrom battery (-) to relay primaryterminal with black/orange or

orange/black wire.Does motor run?

Replace motor relay.

Reverse leads or replace cableif manufactured incorrectly.

Repair or replaceorange/black wire

between motor relay andbattery (-).

Lit. No. 27179 41 July 2001

VEHICLE CONTROL HARNESS TEST

Perform the Motor Test and MotorRelay Test first.

To check the Vehicle Control Harness,the following conditions must be met:

1. The snowplow and vehicle lightingharnesses must be connected.

Is socket #3 of thecontrol plug grounded?

YESYES

YES

NO

YES

NO

NO

NO

No Power To The Control

With the ignition switch in theON position, are there 12volts on pos. C of the # 1connector of the Isolation

Module?

Connect the grounds.Check for a blown fuse or a

faulty connection on theunswitched terminal of the motor

relay.Check switched accessory

lead connection.

YES

Perform Control Test.

Is 12 volts on socket #1of the control plug?

NO

Are vehicle cable assembly andvehicle control harness grounds

connected?

Is 12 volts present on both sidesof the control fuse ?

Using the Isolation ModuleTester, perform the Isolation

Module Test

NO

White 6-Pin Connectoron vehicle control harness

(located in cab)

1

2 5

4

3 6

Socket end view



4. Disconnect the control in the cab.


6. Refer to the 6-pin Connectordiagram. Test the vehicle side ofthe connector in the cab asfollows.

WARNINGThe driver shall keepbystanders clear of the bladeduring this test. Do not standbetween the vehicle and theblade. A moving or fallingblade could cause personalinjury.

Lit. No. 27179 42 July 2001

YES

NO

NO

NO

Is ground on the second motor relay primaryterminal (the black/orange wire)?

Is control power LED on?

Are vehicle cable assembly andvehicle control harness grounds

connected?

Do park/turn lightsfunction on snowplow?

When control is activated (raise, left, orright) is 12 volts on the motor relay primary

terminal (the brown/red wire)?

Motor Relay Will Not Activate

Connect the grounds.

YES

NO

Replace the fuse.

Using the Isolation Module Tester,perform the

Isolation Module Test.

YES

Go to Control Test.

Connect the grounds.

NO

NO

YES PerformMotor Relay Test.

YES

YES

Are vehicle cable assembly and vehiclecontrol harness grounds connected?

NO

YES

Is 7.5-Amp control fuseblown?

VEHICLE CONTROL HARNESS TEST

Lit. No. 27179 43 July 2001

CONTROL TEST

To Safely Handle Hand-Held PCB:

1. Disconnect the control in the caband remove to a workbench.

2. Place control on its left side andremove right side of handle, leavingthe keypad/circuit board assemblyin left half.

3. Touch any grounded metal objectto discharge possible staticbuildup.

1. Disconnect the control in the caband remove to work bench.

2. Perform the Cab Control Testusing the Minute Mount® ElectricalTester.

Do outputs match results ofCab Control Test from Minute

Mount® Electrical Tester?

Control is OK. Verify vehiclecontrol harness ground andpower source for red wire.

Solenoid Control:Replace PCB or control assembly.

Hand-Held Control:Follow handling instructions. Remove handle

half. Is the white cord connector fully seated onthe PCB?

Replace control or proceed by carefullydisconnecting white cord connector from PCB.

Test the cord for continuity according toelectrical schematics. Note internal connectionin the cord. Does continuity match schematic?

Replace PCB.

Seat cord connector fully onthe PCB. Retest Control.

Replace coil cord.

YES

NO NO

NO

YES

YES

Fish-Stik® Hand-held Control or Joystick Solenoid Control

CAUTIONPrinted circuit board (PCB) issubject to damage from staticelectricity. Follow instructionsbelow to safely handle PCB.

4. Remove keypad/circuit boardassembly from housing by onlytouching the edges of the keypad/circuit board assembly.

5. The keypad/circuit boardassembly can be handled safelyas long as contact with it ismaintained.

Lit. No. 27179 44 July 2001

PUMP PRESSURE TEST

1. Check fluid level.

2. Lower blade to the ground toremove any pressure from the liftcylinder.

3 Carefully disconnect the hose forthe base end of the lift cylinder atthe valve manifold block.

4. Using a suitable adapter fitting,attach a 3000 psi pressure gaugeto the valve block fitting.

Snowplow TypeRelief Valve

Approx. turns outfrom fully seated

Pump Relief Pressure PSI± 100 PSI

All Straight Blades 2½ – 2¾ 1750

Adjust pump relief clockwise1/8turn to increase pressure. Did

pressure change?

YESYES

Is motor amp draw greater than190 amps when pump is on

relief?

Remove reservoir. Inspectpickup tube and filter.

Suction side OK?YES

NO

Go to Hydraulic SystemTest.

Remove pump.Is pump O-ring damaged?

YES

Replace Relief Valve andAdjust.

NO

Repair or replace motor.

NO Inspect pump relief valve fordamaged components or

contamination. Is pump reliefvalve good? See pg. 47

Replace pump.

Replace pumpo-ring. Reassemble and

adjust pressure

NO

YES

Is the pressure zero?NO NODoes pump relief pressure

match value on chart?

NO

Remove and inspect pump

Adjust to chart value.

Clean or replace pickup tubeand filter.

YES

YES

5. Activate the raise function with thecontrol and read the pump reliefpressure. The chart lists reliefvalve settings.

WARNINGThe tester shall keepbystanders clear of the bladeduring this test. Do not standbetween vehicle and theblade. A moving or fallingblade could cause personalinjury.

Lit. No. 27179 45 July 2001

CARTRIDGE COIL ACTIVATION TEST

1. Disconnect the red (+) batterycable from the motor andisolate it.

2. Remove solenoid valve cover.

3. Verify wires are properly attachedto solenoid coils. Refer toElectrical Schematic and SolenoidCartridge Valve Identification andLocation Table at top right of thispage.

4. Activate the control for eachfunction and check for magneticpull at all three solenoid valve coilsusing common screwdriver. Onlythe coils designated as "ON" inthe table below should activate foreach function. After noting whichcoils are energized, proceed to theflow chart.

Do activated coils match the chart forall functions?

Verify battery cables are connected. Isground at all black/orange wires attached

to coils?

Repair black/orange wires to coils,check ground connections at motor,

battery cable connector and battery (-)terminal. Retest.

NONO

YESYES

Using Minute Mount® Electrical Tester,perform the Snowplow Harness Test.

Go to Hydraulic System Test.

SolenoidCoil

VehicleControlHarnessSocket

Wire Color Raise Lower AngleRight

AngleLeft

S1 9 White/ Yellow * ON * *S2 4 Light Green ON ONS3 3 Light Blue ON ON

* S1 output is “ON” for all functions if control is in “FLOAT”. Press “RAISE”button to cancel “FLOAT”.

Fish-Stik® Hand-Held Control Only – While in “FLOAT”, pressing and holdingthe “RIGHT” or “LEFT” button turns off solenoid cartridge valve S1 until thebutton is released.)&��

��%��%��

) *

+

Lit. No. 27179 46 July 2001

HYDRAULIC SYSTEM TEST

ACTION REQUESTED PLOW REACTION POSSIBLE CAUSENone S3 not shiftedRaiseAngle Left S2 stuck shifted

S1 not shiftedS2 stuck shifted

Lower None

S3 stuck shifted

Angle Left S3 stuck shiftedNone S2 not shifted

Angle Right

Slow Poppet check valve not openingAngle Right S3 not shiftedRaise S2 not shiftedNone S2 and S3 not shifted

Angle Left

Slow Poppet check valve not openingNone (blade raised) Lowers S1 stuck shifted or has leaking internal check valve

S2 stuck shiftedDrifts RightContamination, bad valve stem seat, or damaged O-ringsin crossover relief valvePoppet check valve open

None

Drifts LeftContamination, bad valve stem seat, or damaged O-ringsin crossover relief valve

This test consists of trying all thesnowplow functions and comparingthe snowplow reaction to the actionrequested in the following table. Thetable will pinpoint faulty solenoidvalves or p/o check valve accurately ifonly one component is malfunctioning.If the snowplow reaction for a givenfunction is not listed in the table, theremay be a relief or p/o check valvewhich is stuck open or contaminated,missing or damaged o-rings or

backing rings on cartridge, relief or p/ocheck valve, or there may be two ormore faulty components. In this case,use the specific function hydraulicschematic and carefully inspect eachcomponent in the flow circuit. Ifcontamination is evident in more thanone component, the hydraulic unit,hoses and cylinders must becompletely disassembled, inspectedand cleaned.

1. Perform Cartridge Coil ActivationTest first.

2. Verify hydraulic hose installation iscorrect. Refer to the HydraulicHose Routing diagram.

3. Test all snowplow functions.

4. Inspect and clean or replace thesuspected component. Refer tothe Hydraulic Unit Parts Diagram.

5. Refer to the sections following thetable for inspecting and adjustingsolenoid cartridge valves, p/ocheck valve, and relief valves.

IMPORTANT: When testing thesnowplow functions, be sure thecontrol is not in “float.”

Lit. No. 27179 47 July 2001

��

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RELIEF VALVE INSPECTION AND ADJUSTMENT

Adjustment

1. Adjust by tightening the relief valvestem until it bottoms out (untilspring is fully compressed).

2. Back off valve stem (rotatecounterclockwise) the number ofturns indicated in the chart.

Relief Valve Inspection

1. Remove the valve stem, ball,spacer and spring.

2. Look for broken or damaged parts,contamination or missing ordamaged O-rings.

3. If parts are in good condition,place ball on hard wood block,hold stem seat on ball and lightlystrike top of stem with a hammer.This seats the ball and valve stem.

4. Apply a light coat of anti-seize orgrease to stem threads. LubricateO-rings with hydraulic fluid.Reassemble components intovalve block.

Hydraulic System

Relief ValveNo. of Turns

Backed Off (CCW)From Fully Seated

Approximate ReliefValve Pressure

± 100 (PSI)Pump Relief * 2½ – 2¾ 1750Angle Cylinder Crossover Relief Regular (RD & HD) 1¼ – 1½ 4000 Commercial (MC) 2¼ – 2½ 2500 LD 2¼ – 2½ 2500

* See Pump Pressure Test to measure actual pump relief pressure. CAUTION

Be careful to strike stemsquarely. You can bend stem ifyou do not strike it squarely.

Lit. No. 27179 48 July 2001

PILOT-OPERATED (POPPET STYLE) CHECK VALVE INSPECTION

1. Strike boss plugs squarely with ahammer to facilitate removal.

2. Remove O-ring boss plug, springand poppet.

3. Remove O-ring boss plug, springand spool with O-ring. Use long/slender needle-nosed pliers toremove spool.

4. Inspect springs, poppet, spool,O-rings and poppet seat for wear,damage or contamination.

5. If the valve manifold block has asteel poppet seat, use a strongpencil magnet to push and pull onthe seat. If the seat moves at all,replace the valve block.

6. Re-oil O-rings, install spool fullyinto bore. Spool must insertsmoothly.

7. Install poppet, springs and O-ringboss plugs. Torque O-ring bossplug to 60 in-lb.

Spool

Back-Up Ring

O-Ring Boss PlugSpring

O-Ring

Poppet

Spring

O-Ring Boss Plug

��,� ��-��

Lit. No. 27179 49 July 2001

1. Remove coils from the solenoidcartridge valves and removecartridge valves from manifold.Look for visible contamination ordamaged seals. Check for stuckspools with a plastic, aluminum, orsoft brass probe by pushing on thespring-loaded internal spool fromthe end of the valve. The spoolshould move freely through itsentire travel.

NOTE: Using probe to move spoolmay shear contamination whichwas affecting spool movement.

2. Bench test the cartridge valve byinstalling a coil on the stem andapplying 12V and ground. Watchthrough the side ports for internalspool travel.

If the cartridge valve spool is stuck orits travel is restricted, replace thecartridge. If the cartridge valve is ingood condition, clean it with partscleaning solvent and dry withcompressed air, being careful not todamage the seals. Check the spooltravel again in case any internalcontaminants were dislodged duringcleaning. Re-oil the cartridge valveseals and o-rings and reinstall the

cartridge valve, torquing to 10 ft-lb.Install the coils and torque retainingnuts to 4 ft-lb.

NOTE: If contamination is seen inmore than one component, it canbe reasonably assumed that theentire system is contaminated andin order to perform a properrepair, the entire hydraulic unitmust be disassembled andcleaned. The hoses and cylindersmust also be disassembled andcleaned. The source of thecontamination must be locatedand repaired before reassembly.

1. Remove both wires from coilterminals.

2. Attach an ohmmeter across thecoil terminals.

3. A reading of approximately 7 ohmsindicates the coil is good. A goodcoil draws approximately 1.5amps.

INDIVIDUAL SOLENOID COIL TEST SOLENOID CARTRIDGE VALVE INSPECTION

��

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Lit. No. 27179 50 July 2001

VEHICLE HEADLAMP TEST

Refer to Electrical Schematic.

To check the vehicle headlamps thefollowing conditions must be met:

1. FISHER® park, turn, and DRLwires (if applicable) must beconnected.




NO LEFT LOW BEAM

Troubleshoot the faulty vehiclecondition.

NONO

Connect to correct Isolation Module connector.

NO

Connect to proper connectors.

Did vehicle left low beamfunction before installing

plug-in harnesses?

YES Is left plug-in harness connected to position4 of the Isolation Module?

YES Is plug-in harness connected tovehicle left headlamp and/or

vehicle connector?

YES

Do headlamps have a negativeor positive common?

Disconnect plug-in harness fromposition 3 of the Isolation Module. Turn

on the headlamps in the low beammode. Is 12 volts on position A of theplug-in harness 10-pin connector?

Is ground on position A of theplug-in harness 10-pin

connector?

Check for faulty connection or amisw ired headlamp connector. Check

for blow n vehicle headlamp fuse.

NEGATIVE

POSITIVE

Using the Isolation ModuleTester, perform the


Disconnect plug-in harness fromposition 3 of the Isolation Module.Turn on the headlamps in the low

beam mode. Is 12 volts onposition K of the plug-in harness

10-pin connector?

YES

YES

NO

YES

NO

NO

NO

Is configuration plug installed andconfiured per instructions?

NOTE: 1999-20_GMC All New Sierraand 1999-20_Chevy Silverado proceed

to positive headlamp test.

Is ground on position K of theplug-in harness 10-pin

connector?

NO

Configure and install configurationplug per instructions.

YES

YES

YES

Lit. No. 27179 51 July 2001

NO RIGHT LOW BEAM

Troubleshoot the faulty vehiclecondition.

NO NO

Connect to correct Isolation Module connector.

NO


Did vehicle right low beam functionbefore installing plug-in harnesses?

YES Is right plug-in harness connected toposition 4 of the Isolation Module?

YES Is plug-in harness connected tovehicle right headlamp and/or

vehicle connector?

YES

Do headlamps have a negativeor positive common?


on the headlamps in the low beammode. Is 12 volts on position A of the

plug-in harness 10-pin connector?

Is ground on position A of theplug-in harness 10-pin

connector?

Check for faulty connection or amiswired headlamp connector. Check

for blown vehicle headlamp fuse.

NEGATIVE

POSITIVE

Is ground on position K of theplug-in harness 10-pin

connector?



Disconnect plug-in harness fromposition 4 of the Isolation Module.Turn on the headlamps in the low

beam mode. Is 12 volts onposition K of the plug-in harness

10-pin connector?

YES YES

YES

NO

YES

NO

NO

NO


Lit. No. 27179 52 July 2001

NO LEFT HIGH BEAM

Troubleshoot the faultyvehicle condition.

NONO

Connect to the correct Isolation Moduleconnector.

NO


Did vehicle left high beam functionbefore installing

plug-in harnesses?

YESIs left plug-in harness connected toposition 3 of the Isolation module?

YES Is plug-in harness connected to vehicleleft headlamp and/or vehicle connector?

YES

Do headlamps have a negative ora positive common?

Disconnect plug-in harness fromposition 3 of Isolation Module. Turn onheadlamps in high beam mode. Is 12

volts on position B of the plug-inharness 10-pin connector?

Is ground on position B of the plug-inharness 10-pin connector?

Check for faulty connection or amiswired headlamp connector. Check

for blown vehicle headlamp fuse.

NEGATIVE

POSITIVE

Is ground on position K of the plug-inharness 10-pin connector?



Disconnect plug-in harness fromposition 3 of Isolation Module. Turn on

headlamps in high beam mode. Is12 volts on position K of the plug-in

harness 10-pin connector?NOTE: Dodge Rams equipped with

sport package (HB1 and HB5headlamps) must also check for

ground on position C.

YES YES

YES

NO

YES

NO

NO

NO


Lit. No. 27179 53 July 2001

NO RIGHT HIGH BEAM

Troubleshoot the faultyvehicle condition.

NO NO

Connect to the correctIsolation Module connector.

NO


Did vehicle right high beam functionbefore installing plug-in

harnesses?

YES Is right plug-in harness connected toposition 4 of theIsolation module?

YES Is the plug-in harness connected to thevehicle right side headlamp and/or vehicle

connector?

YES

Do headlamps have a negativeor a positive common?


on the headlamps in the high beammode. Is 12 volts on position B of theplug-in harness 10-pin connector?

Is ground on position B of the plug-inharness 10-pin connector?

Check for faulty connection or amisw ired headlamp connector. Check

for blow n vehicle headlamp fuse.

NEGATIVE

POSITIVE

Is ground on position K of the plug-inharness 10-pin connector?



Disconnect plug-in harness fromposition 4 of the Isolation Module.Turn on the headlamps in the highbeam mode. Is 12 volts on position

K?NOTE: Dodge Rams equipped w ith

sport package (HB1 and HB5headlamps) must also check for

ground on position C of the plug-inharness 10-pin connector.

YES YES

YES

NO

YES

NO

NO

NO


Lit. No. 27179 54 July 2001

SNOWPLOW HEADLAMP TEST

Refer to Electrical Schematic.

To check the snowplow headlampsthe following conditions must be met:

1. All vehicle lights must befunctioning correctly with theIsolation Module installed. If thevehicle lights are not functioningcorrectly, run the VehicleHeadlamp Test before proceeding.

2. FISHER® park, turn, and DRLwires (if applicable) must beconnected.

3. The snowplow lighting harnessmust be connected to the vehiclelighting harness.


NO LEFT LOW BEAM

Connect both harnesses together.

NO NO

Connect the black wire to the negativebattery terminal.

NO

Connect the black/orange ground wirestogether.

Is the snowplow lighting harnessconnected to the vehicle lighting

harness at the grille?

YES Is the vehicle cable assembly black wireconnected to the negative side of the

battery?

YES Is the black/orange ground wire from thevehicle cable assembly connected to

the vehicle control harness?

Is the black/orange ground wire fromthe vehicle control harness and thevehicle lighting harness connected?

YES

Connect the black/orange groundwires together.

NO

YES

Do headlamps have a negative ora positive common? Remove headlamp bezel. Turn on

headlamps in the low beam mode. Is12 volts on the black wire from the

headlamp plug?

Disconnect vehicle lighting harnessfrom position 2 of Isolation Module.

Is there continuity between position Jof the 10-pin connector and the light

blue wire on the headlamp plug?

Disconnect snowplow lighting andvehicle lighting harnesses at thegrille. Is there continuity between

pin 6 of the snowplow lightingharness plug and the black wire on

the headlight connector?

POSITIVE

Is ground on the light blue wire fromthe headlamp plug?

Using the Isolation Module Tester,perform Isolation Module Test.

Disconnect vehicle lighting harnessfrom position 2 of the Isolation

Module. Is there continuity betweenposition B of the 10-pin connector andthe black wire on the headlamp plug?

Disconnect snowplow lighting andvehicle lighting harnesses at the

grille. Is there continuity between pin11 of the snowplow lighting harness

plug and light blue wire of theheadlamp connector?

Replace snowplow lighting harness.

Replace the sealed beam.


YES

NO

YES

NO

NO

NO

YES

NO

YES

YES


NO

YESNEGATIVE

YES

Replace vehicle lighting harness. Replace vehicle lighting harness.

Go to A

Lit. No. 27179 55 July 2001


YESRemove headlamp bezel. Turn onheadlamps in low beam mode. Is

there ground on the black wire fromthe headlamp plug?


Module. Is there continuity betweenposition J of 10-pin connector and

light blue wire on the headlampplug?


pin 6 of the snowplow lightingharness plug and the black wire on

the headlamp connector?

POSITIVE

Is 12 volts on the light blue wire fromthe headlamp plug?



Module. Is there continuity betweenposition B of the 10-pin connector andthe black wire on the headlamp plug?


grille. Is there continuity between pin11 of the snowplow lighting harnessplug and the light blue wire on the

headlamp connector?




YES

NO

YES

NO

NO

NO

YES

NO

YES

YES


NO

YES

NO LEFT LOW BEAM, CONTINUED


A

Lit. No. 27179 56 July 2001

NO RIGHT LOW BEAM


NO NO


NO





battery?




YES


NO

YES


headlamps in the low beam mode. Is12 volts on the black/white wire from

the headlamp plug?

Disconnect vehicle lighting harnessfrom position 2 of Isolation Module. Isthere continuity between position K of

the 10-pin connector and theblue/orange wire on the headlamp

plug?


pin 1 of the snowplow lightingharness plug and the black/whitewire on the headlamp connector?

POSITIVE

Is ground on the blue/orange wirefrom the headlamp plug?


Disconnect vehicle lighting harnessfrom position 2 of the Isolation Module.Is there continuity between position E

of the 10-pin connector and theblack/white wire on the headlamp

plug?



plug and the blue/orange wire on theheadlamp connector?




YES

NO

YES

NO

NO

NO

YES

NO

YESUsing the Isolation Module Tester,perform Isolation Module Test.

NO

YESNEGATIVE

YES

Replace vehicle lighting harness.YES

Replace vehicle lighting harness.

Go to B


Lit. No. 27179 57 July 2001

YESRemove headlamp bezel. Turn on

headlamps in the low beam mode. Isthere ground on the black/white wire

from the headlamp plug?


Module. Is there continuity betweenposition K of 10-pin connector andblue/orange wire on the headlamp

plug?



plug and the black/white wire on theheadlamp connector?

POSITIVE

Is 12 volts on the blue/orange wirefrom the headlamp plug?


Disconnect vehicle lighting harnessfrom position 2 of the Isolation Module.Is there continuity between position E

of the 10-pin connector and theblack/white wire on the headlamp

plug?



plug and the blue/orange wire on theheadlamp connector?




YES

NO

YES

NO

NO

NO

YES

NO

YES

YES


NO

YES

NO RIGHT LOW BEAM, CONTINUED


B


Lit. No. 27179 58 July 2001

NO LEFT HIGH BEAM


NO NO


NO





battery?




YES


NO

YES


headlamps in the high beam mode.Is 12 volts on the white wire from the

headlamp plug?

Disconnect vehicle lighting harnessfrom position 2 of Isolation Module.

Is there continuity between position Jof the 10-pin connector and the light

blue wire on the headlamp plug?


pin 4 of the snowplow lightingharness plug and the white wire on


POSITIVE

Is ground on the light blue wire fromthe headlamp plug?



Module. Is there continuity betweenposition A of the 10-pin connector andthe white wire on the headlamp plug?


grille. Is there continuity between pin11 of snowplow lighting harness plug

and the light blue wire on theheadlamp connector?




YES

NO

YES

NO

NO

NO

YES

NO

YES

YES


NO

YESNEGATIVE

YES


Go to C


Lit. No. 27179 59 July 2001


headlamps in the high beam mode.Is there ground on the white wire



Module. Is there continuity betweenposition J of 10-pin connector and

light blue wire on the headlamp plug?


pin 4 of the snowplow lightingharness plug and the white wire on


POSITIVE

Is 12 volts on the light blue wire fromthe headlamp plug?



Module. Is there continuity betweenposition A of the 10-pin connector andthe white wire on the headlamp plug?


grille. Is there continuity between pin11 of the snowplow lighting harnessplug and the light blue wire on the

headlamp connector?




YES

NO

YES

NO

NO

NO

YES

NO

YES

YES


NO

YES

NO LEFT HIGH BEAM, CONTINUED


C


Lit. No. 27179 60 July 2001

NO RIGHT HIGH BEAM


NO NO


NO





battery?




YES


NO

YES


headlamps in the high beam mode.Is 12 volts on the white/yellow wire


Disconnect vehicle lighting harnessfrom position 2 of Isolation Module.Is there continuity between positionK of the 10-pin connector and theblue/orange wire on the headlamp

plug?


pin 3 of the snowplow lightingharness plug and the white/yellowwire on the headlamp connector?

POSITIVE

Is ground on the blue/orange wirefrom the headlamp plug?



Module. Is there continuity betweenposition D of the 10-pin connector and

the white/yellow wire on theheadlamp plug?


pin 5 of snowplow lighting harnessplug and the blue/orange wire on the

headlamp connector?




YES

NO

YES

NO

NO

NO

YES

NO

YES

YES


NO

YESNEGATIVE


Go to D


Lit. No. 27179 61 July 2001


headlamps in the high beam mode.Is ground on the white/yellow wire



Module. Is there continuity betweenposition K of 10-pin connector andblue/orange wire on the headlamp

plug?


pin 3 of the snowplow lightingharness plug and the white/yellowwire on the headlamp connector?

POSITIVE

Is 12 volts on the blue/orange wirefrom the headlamp plug?



Module. Is there continuity betweenposition D of the 10-pin connector andthe white/yellow wire on the headlamp

plug?


pin 5 of the snowplow lightingharness plug and the blue/orangewire on the headlamp connector?




YES

NO

YES

NO

NO

NO

YES

NO

YES

YES


NO

YES

NO RIGHT HIGH BEAM, CONTINUED


D


Lit. No. 27179 62 July 2001


YES

NO

Is ground on BLK/ORN wireconnected to the Park/Turn bulb

assemblies?

YES

YES

NO

YES

YESYES YES YES

YESYES

NO

YES

YES

NO

NO NO

NO

NO NO

YES

YES

NO

NO

NO

NO

NO

YES

YES

YES

NO

NO

NO

YES

YES YES

Is snowplow lighting harnessconnected to the vehicle lighting


Is BLK/ORN wire from vehiclecontrol harness and vehicle lighting

harness connected?

Is the BLK/ORN wire from the plowlighting harness connected to the

negative motor terminal?

Connect both harnesses together. Connect BLK/ORN ground wiretogether

Connect BLK/ORN wire to the neg.side of the motor terminal.

Remove left headlamp bezel.Activate the vehicle’s left turn

signal. Is 12 volts present at thejunction of the gray and red wires?

Replace defective bulbs.

Is snowplow Park/Turn fuse blown?

Remove and re-install the Park/Turnbulbs.Remove left headlamp bezel. Is

there continuity between neg. motorterminal and Park/Turn socket

mounting plate?

Replace fuse.

Use Isolation Module Tester toperform Isolation Module Test

On the vehicle lighting harness, isthere continuity between pin 7 of the

vehicle lighting harness plug andPin C of the 10-pin Isolation Module

connector?

Tighten ground screw on Park/TurnBulb Assy.Disconnect vehicle lighting harness

from position 2 of the IsolationModule. Is there continuity betweenposition G of the 10-pin connector

and the junction of the gray and redwires?

On the vehicle lighting harness isthere continuity between pin 2 of thevehicle lighting harness and thenegative terminal of the battery?

Replace vehicle lighting harness.

Disconnect the plug-in harness fromPos. 3 of the Isolation Module. Is there

12 volts on Pos.G of the plug –inharness 10-pin connector? When the

left turn signal is activated?Disconnect snowplow lighting and

vehicle lighting harnesses at the grille.On the snowplow lighting harness, isthere continuity between position 8 of

the snowplow lighting harness plug andthe junction of the gray and red wires?

Check all ground connections.

Check turn signal tap. Checkvehicle turn signal circuit to ensure

it is working correctly.

Is there continuity from Position G ofthe 10-pin connector to the left turn

signal tap?

Are the Park/Turn bulbs seatedcorrectly?

Is vehicle cableAssy. BLK wireconnected toNeg. side of

battery?

Connect both cable assemblies.

Connect blackwire to neg.

battery terminal.

Replace snowplow plug-in harness.

NO

Is plow cableAssy.connectedto vehicle cableAssy. at grille ?

On the vehicle lighting harness, is therecontinuity between Position G of the 10-pin

connector and Position 8 of the vehiclelighting harness plug?Replace snowplow lighting harness

YESNO LEFTSNOWPLOW TURNSIGNAL LAMPS

Lit. No. 27179 63 July 2001


YES

NONO

YES

YESYES

YES

YES

NO

YES

YES

NO

NO

NO

YES

NO NO

YES

YES

NO

NO

NO

NO

NO

YES

YES

YES

NO

NO

NO

YES

YESYES YES

NO

Use Isolation Module Tester toperform Isolation Module Test

On the vehicle lighting harnessis there continuity between pin 2of the vehicle lighting harnessand the negative terminal of thebattery?

Is snowplow lighting harnessconnected to the vehicle lighting


Is BLK/ORN wire from vehiclecontrol harness and vehiclelighting harness connected?

Is the BLK/ORN wire from theplow lighting harness connectedto the negative motor terminal?

Connect both harnessestogether.

Connect BLK/ORN groundwires together.

Connect both cable assemblies.

Connect BLK/ORN wire to theneg. side of the motor terminal.

Remove left headlamp bezel.Activate the vehicle’s left turn

signal. Is 12 volts present at thejunction of the gray and red

wires?

Replace defective bulbs.Is ground on BLK/ORN wireconnected to the Park/Turn bulb

assemblies?

Is snowplow fuse blown?

Remove and re-install thePark/Turn bulbs.Remove right headlamp bezel.

Is there continuity between neg.motor terminal and Park/Turn

socket mounting plate?

Replace fuse.

On the vehicle lighting harness,is there continuity between pin 7of the vehicle lighting harnessplug and Pin C of the 10-pinIsolation Module connector?

Tighten ground screw onPark/Turn Bulb Assy.Disconnect vehicle lighting

harness from position F of theIsolation Module. Is there

continuity between position F ofthe 10-pin connector and the

purple and red wires?

Replace Vehicle LightingHarness.

Disconnect the plug-in harnessfrom Pos. 4 of the Isolation

Module. Is there 12 volts on Pos.Gof the plug –in harness 10-pin

connector? When the vehicle rightturn signal is activated?Disconnect snowplow lighting and

vehicle lighting harnesses at thegrille. On the snowplow lighting

harness, is there continuity betweenposition 9 of the snowplow lighting

harness plug and the junction of thepurple and red wires?


Check turn signal tap. Checkvehicle turn signal circuit to

ensure it is working correctly.

Is there continuity from Position Gof the 10-pin connector to the right

turn signal tap?

Are the Park/Turn bulbs seatedcorrectly?

Connect blackwire to neg.

battery terminal.

Is vehicle cableAssy. BLK wire

connection to Neg.side of batt?

Replace Snowplow plug-in harness.

Is plow cableAssy. connectedto vehicle cableAssy. at grille? YES

On the vehicle lighting harness, is therecontinuity between position G of the 10-pinconnector and position 8 of vehicle lighting

harness plug?Replace Snowplow Lighting Harness

NO RIGHTSNOWPLOW TURNSIGNAL LAMPS

Lit. No. 27179 64 July 2001


NO SNOWPLOW PARKING LIGHTS


NO

Connect black/orn wire tonegative battery terminal.

NOConnect black/orangeground wires together.

Is snowplow lighting harness connectedto vehicle lighting harness at the grille?

YES Is BLK/ORN wire from the plow lightingharness connected to the the negative

motor terminal?

YESIs black/orange ground wire from

vehicle control harness and vehiclelighting harness connected?

YES

Connect black/orange ground wirestogether.

NO YES

Are park/turn bulbs seated correctly?Remove headlamp bezels. Place theheadlamp switch in the park lamp

position. Is 12 volts on the junction ofthe brown wires?

Check, clean and tighten groundconnections on the park/turn socket

mounting plate and on the neg.motor terminal .Disconnect snowplow lighting and

vehicle lighting harnesses at the grille.Is there continuity between pin 10 of

the snowplow lighting harness plug andthe brown wires of the headlamp

assemblies?

Is ground on the black/orange wireconnected to the park/turn bulb

assemblies?


Module. Is there continuity betweenposition H of the 10-pin connector and

the brown wires of the headlampassemblies?

Disconnect the short plug-in harnessfrom the Isolation Module. Is there

continuity from position H of the plug-in harness 10-pin connector to the

park light tap?

Replace fuse.

Replace defective bulbs.YES

YES

NO

YES

NO

YES

YES

Is snowplow park/turn fuse blown?

NO

YES

NO

Disconnect the snowplow lightingand vehicle lighting harnesses at thegrille. On vehicle lighting harness isthere continuity between pin 7 of thevehicle lighting harness and pin c of

the 10-pin Isolation Moduleconnector?

On the vehicle lighting harness isthere continuity between pin 2 of the

vehicle lighting harness and thenegative terminal of the battery?

Remove and reinstall park/turnbulbs.

Using the Isolation Module Tester,perform the Isolation Module Test.


Replace vehicle lighting harness. Replace plug-in harness.Replace vehicle lighting harness.


NO

NO

NO

NO

NO

YES

YES

YES

YES

Remove headlamp bezel. Checkcontinuity between neg. motorterminal and park/turn socket

mounting plates.

Is vehicle cableassy. BLK wire

connected to Neg.side of battery?

Is plow cableassy. connectedto vehicle cableassy. at grille ?

Connect black wire toneg. battery terminal.

NO

NO

NO

YES

NO

Lit. No. 27179 65 July 2001

NO VEHICLE DRLS

Connect to correct IsolationModule connector.

NO NO

Connect to the properconnectors.

NO


Is left plug-in harnessconnected to position 3 of the

Isolation Module?

YES Is the plug-in harnessconnected to the vehicle leftheadlamp(s) and/or vehicle

connector(s)?

YESIs right plug-in harnessconnected to position 4 of the

Isolation Module?

Is plug-in harness connectedto vehicle right headlamp(s)and/or vehicle connector(s)?


YESYES

Connect to the properconnectors.

Is vehicle control harnessconnected to position 1 of

the Isolation Module?

NO

YES

NO

YESIs configuration plugjumpered correctly?

negative common – jumper B to Apositive common – jumper B to C

NOTE: 1999-20_ GMC All New Sierra and1999-20_ Chevy Silverado do not require aconfiguration plug. The vehicle DRLs do not

turn off when the snowplow is attached.

Are the beams used for theDaytime Running Lampsworking properly during

normal headlamp operation?

Configure plug for the correct headlampcommon.

YES

Is the vehicle DRL fuseblown?

Replace any defective bulb(s)and then, using the IsolationModule Tester, perform the


Replace the fuse.YES YES

NO

NO

YES

Investigate vehicle DRLsystem.

NO

To check the vehicle DRL system, thefollowing conditions must be met:

1. Fully understand the operation ofthe vehicle DRL system beforeattempting to troubleshoot DRLproblems on the snowplow.

2. All vehicle lighting systems mustbe functioning correctly before theIsolation Module is installed.

3. The Isolation Module and theassociated harnesses have beeninstalled using the installationinstructions provided.

4. FISHER® DRL wires (if applicable)must be connected.


VEHICLE DAYTIME RUNNING LAMPS (DRL) TEST

Lit. No. 27179 66 July 2001

NO SNOWPLOW DRLS

Connect both harnesses atthe grille?

NO NO

Run the snowplow and vehiclelighting harness tests?

NO

Correct the vehicle problem.

Is snowplow lighting harnessconnected to the vehicle

lighting harness at the grille?

YESAre snowplow headlamps

operating correctly?

YESIs vehicle DRL systemfunctioning correctly?

For 1999-20_ GMC All NewSierra and 1999-20_ ChevySilverado: Disconnect theshort plug-in harness fromthe Isolation Module. Is 12

volts on position F of the 10-pin connector?

For all other vehicles:Refer to paragraph 1 above.

YES

Replace the short plug-inharness.

Using the IsolationModule Tester, performIsolation Module Test.

NO

YES

Is there continuitybetween position F of the10-pin connector and the

pink DRL tap?

YES

Is the pink wire from theplug-in harness

connected to the DRLlamp positive feed wire?

YES

YES

NO

Connect the pink wire.

NO

SNOWPLOW DAYTIME RUNNING LAMPS (DRL) TEST

To check the snowplow DRL system,the following conditions must be met:

1. Fully understand the operation ofthe vehicle DRL system beforeattempting to troubleshoot DRLproblems on the snowplow.

2. All vehicle lighting systems mustbe functioning correctly before theIsolation Module is installed.

3. FISHER® DRL wires (if applicable)must be connected.


Lit. No. 27179 67 July 2001

REMOVABLE SPRING TOOL

To Replace A Spring On The Blade, Follow The Instructions Below.

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CAUTIONServicing the trip springswithout special tools andknowledge could result inpersonal injury. See yourauthorized FISHER® outlet forservice.

1. Insert the threaded rod in throughthe hole in the channel weldment.Be sure the threaded hole in thetab on the rod is nearest to thechannel.

2. Place the assembly on to the topanchor above the spring asillustrated. Be sure to place thespring bar in between the tabs onthe rod. Insert the 1/2 x 1-1/2" Gr.5 cap screw through the outsidetab, through the hole in the springbar, and tighten into the threadedhole.

3. Drop the 1/2" flat washer Gr. 8 overthe threaded rod and fasten thenut to the threaded rod. Tightenthe nut until the spring bar israised enough to insert the pinthrough the pin hole. Center thepin within the hole.

4. Loosen the nut to lower the springbar. Remove the spring toolassembly by removing the1/2" cap screw.

5. Remove the spring from the bladeby removing the bolt from thebottom of the spring bar.

6. Insert the new spring with thespring bar up through the topanchor on the blade. Fasten thebottom of the spring bar to theanchor on the trip edge with thepreviously removed fasteners.Tighten.

7. Repeat steps 1 and 2 above.

8. Repeat step 3 above, exceptremove the pin from the spring bar.

9. Repeat step 4 above.

Lit. No. 27179 68 July 2001

NOTES

Printed in USA

Copyright © 2001Douglas Dynamics. L.L.C. All rights reserved. This material may not be reproduced or copied, in whole or in part, in any printed, mechanical, electronic, film or other distribution and storagemedia, without the written consent of Fisher Engineering. Authorization to photocopy items for internal or personal use by Fisher Engineering outlets is granted.

Fisher Engineering reserves the right under its product improvement policy to change construction or design details and furnish equipment when so altered without reference to illustrations orspecifications used herein. Fisher Engineering and the vehicle manufacturer may require and/or recommend optional equipment for snow removal. This product is manufactured under the followingpatents: 4,280,062, 4,999,935, 5,353,530, 5,420,480, RE35700 and other patents pending. Fisher Engineering offers a limited warranty on all snowplows, spreaders and accessories. See separatelyprinted page for this important information. The following are registered® and unregistered™ trademarks of Douglas Dynamics, L.L.C.: EZ-V®, FISHER®, Fish-Stik®, Insta-Act®, Minute Mount®

A DIVISION OF DOUGLAS DYNAMICS, L.L.C.

Fisher EngineeringP.O. Box 529Rockland, ME 04841

Lit. No. 27179 July 2001

Jeff Plow Manual

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