cooling fan

timmsd · Post by **timmsd** » 14 May 2003, 20:20

Can anyone suggest a solution to the following?
Xantia 1.9Td vsx 1995
Cooling fan is on continuosly even with ignition off. Only one fan is on the other is off.
When I disconnect the 2 sensors on the thermostat housing one does nothing, the other switches the second fan on. The stranges thing is removing both cooling fan fuses from the box inside the engine bay does nothing. In fact I have removed every fuse in the car and it stays on.
I'm stuck!
Dave

blueboy2001 · Post by **blueboy2001** » 14 May 2003, 20:24

Has it got aircon? If so it is most likely the bitron unit playing up.

timmsd · Post by **timmsd** » 14 May 2003, 20:33

yes it has aircon
How do I test the bitron and confirm that it is this, and where is it?
Dave

blueboy2001 · Post by **blueboy2001** » 14 May 2003, 20:41

I've not a clue how to test it, Haynes says send it to a dealer!
The sensor is screwed into the thermostat housing on the left hand end of the cylinder head, and can be identified by a brown connector.
According to Haynes, on some models access is very poor and "other components" may need to be removed to reach it. Good luck!

DLM · Post by **DLM** » 14 May 2003, 20:44

Hmmm - must have gone open circuit somewhere. There isn't an obviously broken/damaged bit of wire insulation anywhere near the fan or its connectors by any chance?
When the fan is in normal operation does it trigger with the ignition off - I seem to remember that Citreons started to do this from the Xantia onward. It may even be designed to operate even in circumstances of dire electrical failure - hence the operation with fuses out, though that could just indicate a very fundamental short-circuit. Perhaps there's a relay for the fan loom that can be swapped out to test? All guesswork from first principles, I'm afraid.
David

timmsd · Post by **timmsd** » 14 May 2003, 20:53

I need to get at the electrical contacts to the 2 fans. They are well hidden. I agree there may well be a short somewhere. This would explain the fuses. The fan does run with the ignition on or off.
Any ideas if there is a relay somewhere that could be fused on?
Dave

DLM · Post by **DLM** » 14 May 2003, 21:14

I guess this might help if you're a dab-hand with the diagrams
http://www.aussiefrogs.com/shane/xantia/xantia.html
David

DLM · Post by **DLM** » 14 May 2003, 21:21

Or a reference to the Bitron module (in XMs) on page 46 of this PDF - it tells you what the thing looks like!
http://herman.kopparkypen.nu/XM/XM1.pdf
David

DLM · Post by **DLM** » 14 May 2003, 21:32

Or even a ref to where you'll find the bitron unit on a Xantia, from this forum?
Hmm... I wish I really did have all this spare time and wasn't just putting off doing the things I SHOULD be doing.... this is the last link I'll post, honestly.
http://www.andyspares.com/discussionfor ... IC_ID=2425
David

AndersDK · Post by **AndersDK** » 15 May 2003, 00:23

David -
That's a very enthusiastic help [:p]
You're setting standards on how to [;)]
Dave -
1 more link on Xantia schematics, in case this covers some bits not found on the other links by David :
http://citroeny.cz/servis/xantiaser/ele ... ektro.html
Take your time browsing the info, then use the best tools you have ready at hand :
Patience, patience & patience [:o)]
Good luck [:)]

wheeler · Post by **wheeler** » 15 May 2003, 07:08

does the stop light come on when the fan is on ? there are 3 cooling fan relays located in between the 2 fans at the front (remove the grille to acsess),because of where they are located facing all the elements it makes them prone to corrosion.the bitron box is located under the L/H/F headlamp,i would guess that this is at fault get a diagram & check feeds/earths to it or swap it with another.there may also be water/corrosion in the connector or box itself.

timmsd · Post by **timmsd** » 15 May 2003, 18:43

Thanks
I was just about to ask where the fan relays are.
On further inspection I have found that there are fuses in the circuit (40A) behind the battery and abs module. Disconnecting one of these stops the fan. I have spent a happy hour removing and replacing each relay with no joy. My prime suspect is now a fused relay, or a buggered sensor however:
if I disconnect the bitron sensor the second fan starts - high resistance making it think it is hot?
if I disconnect the other sensor the fan stays on.
Next step - locate and find the relay.
Agree?
Dave

DLM · Post by **DLM** » 15 May 2003, 21:54

Good luck with that thar' relay swappin'/huntin'(or even just contact-cleaning?). My unknowledgable guess is that while the first fan is permanently triggered, the second one will come one whenever there's an appropriate input (or lack if it). I'm also assuming that the thermo switches are "breakers" rather than "makers", though that's probably far too simplistic for a car more modern than my BX.
David
PS - mullet fishing could seem distinctly relaxing after this, Dave, and more predictable!

wheeler · Post by **wheeler** » 15 May 2003, 23:35

the sensor (brown plug) is not a maker or breaker,its a PTC type sensor.if you disconnect the sensor the other fan starts because it thinks there is a fault with it & it goes into a kind of back up mode to stop it overheating.check out thoes relays first.when you remove the front grille the 3 of them are under a black cover held on with a screw that sits in between the two fans.open the relays up & have a look inside.

timmsd · Post by **timmsd** » 22 May 2003, 22:24

Well thanks to all that replied. Thaks especially to wheeler. Found the relays and would never have thought to look there. I expected them to be with the others of such. Anyway it was a fused relay and all works fine now.
Yet again this forum has been really helpful.