Air con always on (xantia year 2000)

Post your Cit/Peu/Ren air conditioning queries or advice.

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howzat
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Air con always on (xantia year 2000)

Post by howzat » 08 Mar 2007, 22:41

My problem is that the compressor engages with air con switch off. This causes fans to operate. Switching on the system lights the indicator in the switch. Unplugging the compressor disengages it. I need a wiring diagram of the system and location of the various relays. Any suggestions would be appreciated.
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alan s
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Post by alan s » 08 Mar 2007, 23:49

You might try trawling through a few of Clogzz postings as he has some valuable info and wiring diagrams. If no luck, then try sending him a PM as I understand his internet access is limited at present.
Failing that, I'd be looking at the switch that activates it possibly having frozen contacts, the relays being frozen shut or wires that may be trapped causing them to be bridged prior to the switch.


Alan S
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Clogzz
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Post by Clogzz » 10 Mar 2007, 14:09

Sorry for the delay. :oops:
Here is a map of the air conditioning control, in French unfortunately, but let me know if anything needs translating.

Image

The fault is certain to be as Alan explains, because you have a switching fault only, since both the compressor and the fans operate, as they should when the aircon gets switched on.
Best wishes, and keep us posted. :)
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howzat
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Xantia air con

Post by howzat » 13 Mar 2007, 23:10

Thanks for the circuit diagram Clogzz, it is very useful. I will let you know how I get on .
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howzat
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Xantia air con

Post by howzat » 15 Mar 2007, 21:03

Had a quick look for relevant relays. Could only find one under the cover behind the battery. According to the circuit diag 3 relays work the fans and two more the compressor clutch. Where are they hiding? Suggestions welcomed.
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Post by Clogzz » 16 Mar 2007, 15:52

The other compressor relay is on the climate control board under the dash.
This link has a clickable map: :mrgreen:

http://www.peugeotlogic.com/workshop/ws ... /ac405.htm

The fan relays are between the fans at the front:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17012
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howzat
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Xantia air con

Post by howzat » 27 Mar 2007, 22:30

I have had a further poke round to try to get some indication as to where the fault lies without dismantling too much.
If I unplug the connection to the compressor (with the engine running) and then reconnect it the clutch does not engage immediately but does so after about 30 secs. If I press the aircon switch the clutch engages immediately suggesting the switch is OK.
Does the ecu under the left hand headlight have anything to do with the compressor or does it just control the fans.
According to the circuit diagram the feed from the calculateur climatisation goes through two relays, the relais compressor and the relais coupure compresseur. However both these relays are shown as being in the "make" position when not energised and so should not be causing the problem. There appears to be a connection fom the fan controller onto the feed to the compressor.
One of the articles states that the compressor relay is part of the aircon controller but the circuit diagram shows it as separate. I am going to try removing the various fuses to see if de-activating parts of the circuit gives any clues.
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Post by Clogzz » 28 Mar 2007, 14:32

About 11:30 PM here, a bit late to do some clear thinking. Image
Pins 5 & 13 of the Bitron under the headlamp are inputs from the air conditioning to switch the fans.
The only Bitron function that has to do with the compressor is the output on pin 11 to the compressor relay, which is energised to release the clutch.
The maps are for the Mk I, with differences for the Mk II being that the blower motor is supplied through a relay switched with the ignition key, and the aircon being switched on when the ventilation slider is set to ‘demist’.
That’s for the vintage 2000 Mk II, some earlier vintages don’t switch on the aircon when set to ‘demist’.
I’ll have to do some more map reading to be able to be of more use.
All the maps and pictures of aircon that I have are in this bucket: :mrgreen:

http://s132.photobucket.com/albums/q23/Clogzz/

Edit Thursday: Delayed reaction, :oops: should have thought of that when reading the first post, as the ‘demist’ setting will automatically turn on the aircon of the later Mk II’s.
It looks like the transition to Mk II wasn’t done overnight, and there are what the French call ‘evolutions’ along the way. :roll:
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howzat
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Xantia air con

Post by howzat » 29 Mar 2007, 15:20

Congratulations Clogzz you solved the problem. Here in damp UK we have the demister on most of the time and that was switching on the aircon. As soon as I read your reply I thought thats got to be the cause and so it was. Thank you for saving me time and expense and for providing so much useful info which will no doubt be useful in the future. :D
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