AC Controller problems

[George Sidman]

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 montereynet.net
Monterey Network Center
9701 Blue Larkspur Lane
Monterey, CA  93940
831.657.1510