Xantia electrical gremlins

[tonyc]

Hi, I have a 2000 HDI Exclusive that has been attacked by the gremlins. Just back from France where the air con and heater blower stopped for no reason. (the radiator fans also stopped but this was because the aircon was off) Suspecting the resistor on the heater blower I checked the supply to the plug but nothing! Citroen France wanted €185 for the resistor and neither being rich nor certain this would cure the problem I decided to roast for the rest of the holiday. 4 days later with no explanation everything kicked off again and is still working. A couple of other pointers or maybe red herrings, the heater fan would sometimes stop or at least slow when slowing down for junctions and resume normal speed when accelerating. The clock has had a mind of it's own since I bought the car, just fading away then returning with zero's displayed, somtimes several times a day sometimes working ok for days. A new clock didn't fix the problem.
I've heard of a problem with the ignition switch but thought it was only on early cars. Anyone got any ideas please? Tony

[volcane]

Oh Mate, it sounds like you have a friday afternoon car there,
Maybe something to do with a control module or may even just be a simple earth problem. Good luck

[Ripsnort]

try running a seperate earth to the clock,from the battery terminal, and see what you get. It might give you a clue to the other probs if the clock is ok.

[DocBrown]

On older Xantia's a worn ignition switch could cause unusual electrical symptoms. The same fault can occur since it is a switch and switches do wear out especially when a big bunch of keys is swinging from it for thousands of miles.

I would check every earth connection under the bonnet. There should be no corrosion of the cable or the ring terminal where the earth bolts to the metal bodywork.
Then make sure the fuse and relay boxes are secure and show no signs of water ingress, or overheating. Any cables and wires to and from these units should also be secure, intact and none of that greenish corrosion that is often seen on old copper cables and wires.
Make sure battery terminals are secure and clean and corrosion free.
With the heater/ventilation fan switch on maximum speed there is no resistor between fan motor and feed - thus there should be 12 volts reading at fan motor connector. If not then there is a break (albeit temporary) between the motor and source. Check fuse box for blown or loose fuses and possible dodgy connector. Make sure nothing's come adrift
Does the instrument lights dim or glow brighter when revving car or slowing down? If so it could mean the output of the alternator is not keeping within the 13.5 to 14.7 volt range. Maybe a long shot but worth checking out.

Let us know if you find anything.

[tonyc]

Well, this car seems to have been self healing. Since the French trip the aircon has been ok until tonight when once again nothing. I've stripped the dash and dismantled the ignition switch but so far nothing. Does anyone have details of fitting a relay outside of the ignitin switch? Maybe worth mentioning the blower has been slowing slighly when turning but nothing seems amiss around the steering column.
The clock however still does as it pleases
Cheers Tony