Citroen XM Forum

Hi Everyone, Im in trouble with cooling fans, not working at all, have viewed old post and gleaned some info. and cleaned the three green relays above headlights nearside, they were pretty bad with green corrosion, sqirted some wd 40 over contacts after cleaning with dremel type machine etc. tried to see if fans are working, of course not! so now have Bitron out, it looks fine, now to my question can or how do I test it, 2nd, question can the car be used without re-connecting it? also I believe there is a temperature sensor somewhere but Im danged if I can find it, can some kind gent point out where it is and what it looks like. I am hopeing the big boil up I had in Plymouth city center,(i dislike citys) hasen't ruined the engine, the temp gauge was off the clock and being stuck in center lane of three coulden't pull over, eventually managed to stop on extra wide pavement, by now it looked more like a steam engine,waited three quaters of hour before cool enough to drive, then into traffic again STOP IMMEDIATELY ETC on displays, so 50 yards around corner into bus bay, into nearest house, water can full into rad, thank man and away, stop start, road works, every stop off engine, eventually out of traffic and temp stayed at 90 or there about with wind blowing through rad, so far no bad effects. Hope haven't bored you to tears with my saga. Bob.H.
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Bob,

Unless I've missed it and you have posted this elseware then this area of the forum is really the wrong place for this sort of question. Maybe a repost to the appropriate area (Electrical perhaps) will elicit some positive responses as to the fan problem.

Maybe a mod can move this post for you.

Sorry I can't help. Now if it was a Xantia I could...

Bob,
When it happened to mine i went straight down the scappies and bought another, fitted it job done.

Regards,
Norman

Hi Jim, Thanks for the advise, now if I can find how to move the post.

Hi Norman, Thanks for advise, Unfortunately the chance of finding a xm at a local scrapyard is remote, xm's in this area are like hens teeth, infact not seen one since I purchased this one two years ago, maybe the xantia has a bitron to fit? Bob.

bobhowes wrote:maybe the xantia has a bitron to fit? Bob.

It does but whether or not it's the same one I sadly don't know yet. If you want one out of a Xantia it's a hell of a job; it lives under the NS headlight but to get at it you need to take the whole of the front of the car off and that's nowhere as easy as on the XM...

I'd be thinking one or other of the actual fans might be the cause. Again, I may be wrong for the XM but in a Xantia the basic health of the system can be established by disconnecting the Bitron (brown) sensor at the thermostat housing and then the fans should spring into life at full-speed. This is a fail-safe should the sensor go AWOL. Another quick test is to pop the aircon on and the fans should run at half-speed.

If both the fans run at full speed then they're good. If only one fan runs then this indicates the other may be open-circuit. This will prevent the fans running at half-speed as for this they are wired in series.

Sometimes the fault is sticky brushes and poking the fan blades with a long stick may provoke some life from them.

I'd be surprised if the XM and Xantia don't share fans.

Non-aircon cars do not use a Bitron to control the fans; they're controlled by a thermoswitch in the side of the rad and this is a well-known unreliable component...

Normally it's an admin job to move a post. I'm not sure if the mods on here can do it...

Jim Im going out now and disconnect the brown sensor and if fans dont work will give them a good pokeing, its lucky I dont do much city work so dont get in traffic jams, car is fine when wind is blowing through rad. Bob.