xantia air con

weety · Unread post by **weety** » 08 Feb 2005, 23:33

Hi guys my aircon is really weird i have been trying to get it to works for months on and off now so i thought i would plead for help again......
OK it has climate control so (in theory) you set it to a temperature and it should attain that temperature and hold it.....if you set it to the bottom of the scale it should just produce cold air...if you set it to the top just hot air.
So what it actually does is...
set at the bottom of the scale....... produces endless hot air
set at the top of the scale.......... produces mostly cold air with occasional blasts of hot air
set for a specific temperature....... tries to hold a temperature...but not the one set, if you set it for a temperature
at the top end of the scale its colder than when set to one at the bottom end of the scale.
Also if you do anything that would heat the coolant up (eg drive fast up a motorway hill) you get a burst of hot air whatever it is set on.
So my only thoughts are maybe some wires have been put in backwards by some bodger prior to me.....but what actually controls the temperature is it the little fan behind the alarm light or does that 'report back' to a control box somewhere else?
any help would be gratefully appreciated
cheers

Unread post by **alan s** » 09 Feb 2005, 02:40

Something's definitely bottoms up there.
I haven't had cause to delve too far into the climate controls on these but obviously they have both hot and cold controls. I gather this from the sensation I sometimes get when I have the outside thermometer pointing at 38 - 40 degrees, feel it's set a bit too cold, reset the temp a couple of degrees and suddenly get 'that smell' that happens as the heaters turn on; tends to cause panics in those temps[:0]
I would suspect that someone, somewhere, somehow has managed to wire the sensor for the heater and sensors for the air/con in such a manner so that it thinks everything is opposite to what it is, so if you were to set the temp at say 22, then decide to warm it up and set it at 24, in reality, you'd get 20. If you can get hold of a wiring diagram would be the simplest way as I feel once you could trace the wiring paricularly to the sensor area, it wouldn't be all that hard to sort.
Failing this, any way of distinguishing one sensor from the other eith by shape, colour or markings would give you a starting basis. The small underdash fan I presume is working as it should?
Alan S

Unread post by **RichardW** » 10 Feb 2005, 00:22

There's a box of tricks somwhere - don't know where though!
It takes inputs from the sensor behind the alarm LED and the position of the temp slider at least (I suspect it also reads the coolant temperature). Then adjusts the fan (if set to auto) and a flap over the heater matrix to adjust the air temp.
Clearly your servo motor is either connected the wrong way around, or it has gone 'over centre' and is responding the wrong way. Don't know where the servo motor is though - dashboard removal required to get at it [?][xx(]
I think it might read the coolant temp, then preemptively close the flap if it detects a sudden rise in coolant temp - hence yours responds in the opposite direction and opens the flap.

weety · Unread post by **weety** » 10 Feb 2005, 02:49

hmmm dashboard removal.....maybe i will just open the window......i might replace the fan unit behind the alarm led it still spins and looks ok but at least i can get at that!