Xantia Fan info required.

alan s · Post by **alan s** » 19 Mar 2004, 16:47

We have a guy over here who has a Xantia & apparently both his fans have stopped.
Can someone tell me where to start looking to troubleshoot please?
It sounds to me like a possible sensor or a relay. He has had an Aussie "Specialist" tell him that both fans are caput that I find a bit fanciful but then quoted (honest, I'm not joking) A$1200 for new fans so it's important to get this info to do a double check on it.
Needless to say it's a petrol (possibly 2 litre) and as he says <b>fans</b> (plural) it should have air/con.
Alan S

Post by **RichardW** » 19 Mar 2004, 17:26

Yep, there should be two fans on the rad (which is what I assume you are talking about?). And yes, they not cheap over here either AIUI! First test of course should be 12V across the fans to see if they will run - doubt both are knackered at the same time!Fans should always run at the same time - either low or high speed. Both should come on low speed when the air con is switched on. Fan function is, AFAIK, on A/C cars controlled by the Bitron unit, but there are some relays somewhere. From what I have heard the bitron moves around the engine bay depending on how many glasses of vin rouge the fitter had had at lunch time - ditto the relays, but they might be down behind the bumpers somewhere (in fact I think this is the case as I am sure I have read about these relays getting corroded and causing a non operation scenario). Default operation for the Bitron is for the fans to run all the time I think, so this points to a fuse or relay fault. Oh, and disconnect the battery or fuse before you stuff your hand in there as the fans are always live and might start at any time - even with the ignition off!

AndersDK · Post by **AndersDK** » 19 Mar 2004, 18:58

Richard -
Clearly you had your war with this on the xantia -
Are you able to see if this applies for other Xantia models than the 1.9TD :
http://citroeny.cz/servis/xantiaser/klima/klima.htm

Post by **RichardW** » 19 Mar 2004, 19:35

Anders,
Not had this war - yet! This just my understanding from reading others' posts.
I have had a look at the wiring diagram (in Haynes!) for air-con petrol models and most of what I said is rubbish[:I]! There appears to be only 1 relay, with the Bitron controller doing everything else. Not clear from the diagram how (or indeed if!) the Bitron can make different fan speeds. It can still start with the ignition off though... It's also not clear if bridging out the temperature sensor will start the fans - although as it appears to be a RTD it probably will. Interestingly, there is a connection to the 'Diagnostic Socket' shown which should show if the fan is getting juice or not.

jozivic · Post by **jozivic** » 19 Mar 2004, 20:02

For my opinion the problem is in the main switch in cabin which is almost on the same place (AUTO). If you moving it left and right quickly, you solve the problem for a day or two. I think it have to be from platinum and not in cheap version. I have problems on old Xantia with this switch too. But any 80.000 km's you have to change brushes in main motor of climate in cabin to prevent burning of motor. Motor is simple one, but it is hard to find spare brushes. Any good auto-electrician is capable to adapt it, you have carefully to observe the % in mix copper-charcoal.

BonceChops · Post by **BonceChops** » 19 Mar 2004, 20:18

Is low speed not both fans in series and high speed both fans in parallel?
Neil

Stempy · Post by **Stempy** » 19 Mar 2004, 23:08

I think you have hit the nail on the head Neil. I've been playing with my HVAC system and I think I'm gradually getting it to work as it should, but what with two fans with two speeds and aircon, bitron, thermostat, senders, relays etc etc all interdependent, it's hard to know exactly how the designers meant it to work.

wheeler · Post by **wheeler** » 20 Mar 2004, 00:24

neil is correct about the series/parallel arangement for the fans on different speeds.there are three relays located in between the two fans under a small black cover that control them.these relays are prone to corrosion becase of where they are located.also if one fan motor is faulty it can give the impession that both are gone,if it has A/C & bitron if you unplug the 2 pin brown connector on the temp sensor in the thermostat housing the fans should kick in at full speed.after those checks you really need the correct wiring diagram to check it further.