Heater Motor & Display Screen, A few observations!

[Robin]

Well, time to share my thoughts on an afternoons wet distraction. Not being able to do the work I scheduled which was on a boat I turned to the couple of annoyances on the XM. It's a 97 Mk2 2.5TD estate at 148k miles.

First the heater fan motor - this would be fine for several days and then being of an intelligent disposition new precisely when to go AWOL, generally when it was cold in standing traffic or when the screen needed demisting

The cause of the problem was sticking brushes at the armature. Easily dealt with and the motor does dismantle enough to get in and clean the brush housings and armature and happily when they get too short, which will be fairly soon, they can be changed. I suspect it will mean filing down bigger ones though from a dynamo or similar.

Within the diode speed control pack housed in the motors main plastic body there is an exposed/uncased relay which after removing the motor, can be seen once the diode control pack has been removed - two philips self tappers - this area is exposed to all the damp and salt laden air that comes into the heater motor so expect a bit of a battle. You can remove the motor from the housing by prying it out of its three rubber mounts but remove the short cable loom which has a plug at the motor end and spade terminals at the other into the diode pack housing.
I think this relay could be the cause of some difficult symptoms, erratic fan running, tripping out etc. Certainly the one here is working very hard in dreadful conditions so it was cleaned and lubricated to assist with corrosion reduction. Careful what you use for lubrication as oils can causing burning of the contacts and make matters worse.

Reassembly etc as per the HBOL.

The dash board display. L/H unit with all the messages.

I have been able to dismantle both the early and later types and the early ones are far better built and assembled than the later ones with the ribbon connection. However having lost around eighteen lines I thought it was time to expore the possibilities. I could not use the parts from the early one directly to repair the later version but I am sure someone with more knowledge could possibly cobble it together.
The problem as we know is the failure of the contact along the ribbon with he screen or PCB. It is all held in place with a rubber gasket that provides the constant pressure along the ribbon edge. By running my finger nail (tool number 6 in the electronics toolkit) along the ribbon edge and ensuring the contact was as firm and close as possible plus changing the 'O' ring style gasket for a new one out of my 'O' ring set because the original one distorts and shrinks, I have all the lines back except one.

I have to say that working in the spacious cabin with the radio on in a comfy seat helps to compensate for the irritations of owning an XM

Happy motoring all, Robin

[citroenxm]

Robin

Yeah, its a great shame that S1 L/h displays are not compatible with S2 cars.

S1 displays were made in house by citroen (I think) but later ones the electronics were made in China or somewhere and quality was down

The plugs on the rear are the same, but plug a S1 display into a S2 car and nothing happens...

Its rare an S1 breaks down, which is a shame, as I have about 5 S1 displays in stock but no market for them as they dont break down...

Shame

Regards
citroenxm