Repairing missing lines on the Citroen XM dot matrix...

Repairing missing lines on the Citroen XM dot matrix display

Overview

The dot matrix display on the series 2 XM alerts the driver to a recent suspension mode change, open doors, including the boot and bonnet, radio information and significant engine warnings such as low oil and water levels. More specific information can be found in the XM handbook.

The display has a habit of loosing lines which, after a while, can make the text difficult to read. The most common reason for this is the glue that attaches the ribbon to the PCB, and the rubber ring which keeps it pushed in place, both degrade. If, after following this guide you still have lines out, the glue between the matrix and ribbon could be degrading, though why this is less common I don't know. This guide only deals with the former issue.

The outcome of this guide isn't really designed to be a permanent repair, it may last two minutes, it may last 20 years, no guarantees.

There is a more permanent solution available involving a piece of rubber with carbon tracks on it that completely replaces the ribbon but if you can get hold of it, you'll pay a couple of notes for it.

Tools

T20 and T9 Torx keysSmall flat screwdriverNail varnish removerCotton budSmall craft knifeSmall cable tie6B pencil, HB may do but the higher the B the betterTapeSpare bulbs

Firstly, disconnect the battery

Repairing missing lines on the Citroen XM dot matrix display Kevin Sanders 2011

Removing the lower steering wheel cowel

There are five T20 screws that need removing (Fig 1-5).


Fig 3: Above the height and rake adjuster Fig 4: Bottom left behind the height and

rake adjuster

Fig 5: Recessed in the oval shaped hole

Fig 2: Under the left stalkFig 1: Under the right stalk

Pull the lower cowel downwards (Fig 6), unplug the ignition key light and remove the lower cowel. You may find it helpful to release the height and rake adjustment lever. If you have cruise control, you will probably have a bit of fun with that stalk.

At this point, the upper cowling should be free to move around a bit, its not a requirement to remove it but it does help, I'm going to be leaving mine in place just because I can. If you do remove it then take out the stalk multi plugs (Fig 7-8).


Fig 6: Removing the lower cowel

Fig 7: Left stalk plug, go for the grey one first, tab is on the hidden side, same for the white one after grey is unplugged

Fig 8: Right stalk plug, note the release tab on the top

Partially removing the display surrounding

There are eight T20 screws to remove, one hidden behind the alarm LED (Fig 9), which can be prised off with a fingernail or screwdriver. The next three run along the bottom of the panel (Fig 10). Another two in recesses above the lighting rheostat (Fig 11), take note of the clip here.

The last two are hidden behind bits of plastic behind the steering wheel. Its a good idea to adjust the height and rake then lock it, especially if the upper cowling is left on. These clips can be removed with a small screwdriver or fingernail to unclip the nearest bit (Fig 13) then pulled parallel to the surrounding plastic (Fig 12).


Fig 9: Screw hidden behind the alarm LED

Fig 11: Two screws in the recesses, note the clip in the oval bit

Fig 13: Unclipping the plastic cover

Fig 10: Three screws running along the bottom

Fig 14: Both covers removed showing the remaining two T20 screws

Unclip the bottom clip mentioned earlier and the whole unit should pull towards you (Fig 14). There should be enough space to remove the display without disconnecting any unrelated wiring.

Removing the display unit

This next bit is the most difficult part so far, it will be much easier with a photo of it partially removed, so I've put a big one up (Fig 15). You need to unclip those two clips with a small flat screwdriver and tilt the display back as if it was hinging on the bottom.


Fig 14: The lower cowling is just a trick of the light, it's not actually there...

Fig 15: Display partially removed to show the hidden clips that need to be unclipped

Pull the display up out of its home and remove the wire, there is a tab on the top and a handle to pull on (Fig 16).

Fixing the lines

A picture may paint 1000 words but a video paints rather a lot more so I decided to film the next bit, a link can be found in the thread...but not yet...

Refitting

Reverse of removal.


Fig 16: Remove the connector by pressing the tab and pulling the handle

Repairing missing lines on the Citroen XM dot matrix...

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