Xantia - Bitron info needed

[davek-uk]

My a/c has always been fine and the cooling fans work, as they should. Over the recent hot spell a problem has appeared and I have no idea what to check!
I left the other half and the dogs in a/c splendour whilst I popped into a shop. Getting back I was surprised to find the cooling fans on full blast – I've never heard full blast before. Indicated temperature was below, but near, 80ºC – quite normal as the a/c always puts the fans on half speed.
Since then at idle I get the engine diagnostic warning light on and if the engine is hot enough the fans kick in at full speed. Oddly enough the reading on the temp gauge need not be very high. Normal running temp with the fans at half speed is between 75ºC and 80ºC – only hitting 80ºC after thrashing up hill. Without a/c the half speed cuts in at about 83ºC and cuts out at 79ºC.
Except for the engine diagnostic warning light, I'd be happy if the fans switched one speed up at the same temperature (83ºC) – that would seem logical.
I get the engine diagnostic warning light on a second or two after the car is left to idle, even when the engine is cold.
Experimenting, I pulled the electrical connection off of the a/c drier bottle and the engine diagnostic warning light went out. Incidentally I also noticed some clear, slimy fluid on one of the drier bottle pipes (the lower one) that had dripped down to the front frame. Is this linked? A leak or condensation?
I have read the forum and know the bitron box controls the a/c and cooling fans, but does it have an input to the engine diagnostic warning light and what does the screw in attachment with the wires do on the drier bottle? I'm wondering if the a/c system has detected a leak but I'm unsure if this would be noticed and/or reported this way. Any ideas anyone?

[alan s]

The high speed fan would have come on as a safeguard when you left the car sitting idling in the car park; not a real good practice although it does happen often. A mate of mine who is a fridge/air con mechanic often tells me that he has to smile when he is working at the local shopping centres in Summer where outside temps hit the high 40s C and hears the Bang.....hisss coming from various parts of the car park as the discharge hoses blow on the cars that have been left idling in the car park with the air/con running. Anything that causes the head pressure to rise, that switch you refer to on top of the reciver/dryer should chop in, make the fans go full blast and thereby reduce the head pressures, In our cases, the air is so hot the pipes blow before the pressures drop.
Don't know why the light is coming on now though; suggest you disconnect the battery and wipe the memory and see if that makes a difference.
Check also to see if both the fans are turning on when the air/con is activated as if only one fan is operating, this tends to cause the head pressure to build up quickly and trigger the hP switch.
The oil at the fitting is almost certainly a sign of a leak and could also have a bearing on any erratic running. If the head pressure really went over the top it could be a one off leak but more likely may have unseated the "O" ring on the fitting and may require a new "O" ring there as well as along the discharge line at other fittings.
As aprecaution, I'd be inclined to replace the "O" rings and the receiver/drier and get the system evacuated and recharged at the same time. I think you'll find that will overcome all the problems. I'd also get out of the habit of leaving the car with the air/con operating for more than a couple of minutes if I were you.
Alan S
Alan S

[davek-uk]

Thanks for that Alan. So it was the a/c system pressure that was building up. Ran the a/c again yesterday and I didn't notice the leak but I will get it checked out and serviced. Looking at the drier bottle it looks as if nothing has been changed since new so I guess it's overdue a service.
In my further investigations, I unplugged the brown temp sensor near the thermostat and the fans ran full speed as they should. I also noticed that this put the engine diagnostic warning light on too. So the Briton unit has an input to this light when it recognises an error.
Both fans run together at either half or full speed, so at least they are ok.

[nelliened]

hi im new to all this forum stuff so please accept my apologies if i sound a bit cranky !!!

i have a 2001 xantia hdi 110 with aircon -the red temprature light has just statred flashing with the stop - i have noticed that the fans are not coming on with the air con can anyone help !!!!!

[Clogzz]

How cold is it in Hull ?
The air conditioning won't work unless it's about 5 or 6ºC.
There's a brown temperature sensor and its wiring that cause this fault:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17472

Next occasion, better start a new thread of your own, otherwise we might be answering to old queries.