AC Controller problems

Henry A Harper III hah at
Thu Jan 9 15:35:42 EST 2003

Since the heater cutoff valve is vacuum contolled by the programmer, it
makes sense to check that it moves when the interior setpoint is exercised
from full cold to full hot. I think that the default/failure mode of the
climate control system is supposed to be (hot) defrost, so maybe one of
your foam blocks is working a little too well or not all? Bentley has

Henry Harper  hah at
1991 200 quattro, 116k
1988 GTI 16v, 233k

On Thursday, January 09, 2003 11:04 AM, George Sidman
[SMTP:sidman at] wrote:
> A few months ago the AC controller behind the glove box began hissing
> and the climate control got very flakey. Obviously it was leaking it's
> vacuum. I got a new one from Didi at Carlsen, but noted when I
> installed it that the mfr date was 1991. It too hissed so I pulled it
> out. So last weekend I took the original apart and discovered that the
> small square foam pads behind the vacuum solenoids were all rotted;
> not holding the vacuum. Didi tells me that Audi has 5 left in stock
> and they are all dated 1991. The "new" one from Didi had rotted blocks
> as well, so we can assume the others in stock are probably no good.
> I replaced the rot with new neoprene foam blocks, and tested the
> vacuum with my Mighty Vac, and all appeared good. Upon re-installation
> there was no hiss, but the system only delivers refrigerated air - and
> no heat. What the?????
> Any BTDT ot other advice?
> --
> George Sidman, President
> sidman at
> Monterey Network Center
> 9701 Blue Larkspur Lane
> Monterey, CA  93940
> 831.657.1510
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