Heating/ac problem

tom.w

Active Member
Aug 6, 2017
1
0
Hi, I have a 2003 1.2 Seat Ibiza, i don't know a great deal about cars, but i'm fairly handy fixing things when i know how.
The heating/ac has a mind of its own. If it's hot outside and I have the temperature dial down to low, and the a/c on, occasionally for no reason the heat will come on full blast and it won't go off until i open the windows, turn the fan on/off a bunch of times. It's thermostatic, not manual, so i guess if the temp gets "too cold" in the car, will it trigger the heating? Does the dial relate to the temp of the air coming out, or the temp in the car? There also doesn't seem to be any option of just warm air. It's either freezing cold or boiling hot at any one time, and adjusting the dial doesn't seem to change anything. There is no mixing happening at all, is there supposed to be? The recirculation button randomly goes on and off aswell.
Any thoughts appreciated. Squirrels?
Thanks
 
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RUM4MO

Active Member
Jun 4, 2008
7,784
983
South Scotland
I think that the temperature control flap motor assembly has become faulty. What happens is, either you or the auto controller demand a temperature or change in temperature, to achieve this, there is a motorises flap controlling which route the incoming air will take to provide that cabin temperature, so either it passes the air over the heater matrix or over the AC evaporator, or a blend of both.

Try leaving the AC off and demanding cold air, if sometimes it gives out hot air then you have found your problem.

As a stop gap, maybe try demanding Hi and a few seconds later Lo and repeat that a few times, that might keep it working for a day/week/month.

These flap motors have a potentiometer as positional feedback to the controller, it will probably be that potentiometer track that is now a bit dirty, this is a very common VWG issue and has been for many many years.

Once, when I had a 2000 VW Passat 4Motion, we had to stop at motorway services to cool off, and leave the car doors open to cool it off, after that I finally replaced the temperature flap motor, they are not cheap and I'd doubt if there is anything to gain by fitting a used one as it might not have "long to go" before it too is faulty.

Find the number on a parts listing online and look on ebay for NOS? Maybe before that, find out where it is located as they can be a bit tricky to reach under the centre console area.

Edit:- http://www.oemepc.com/ this is a link to the parts listing, you will find the correct part number in there, it might take some time to find it!
 
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