Automatic Climate Control 1990 Audi 100

[cobram at juno.com]

Likely the vacuum solenoids inside the CC box are on their way out. 
There are 4 of them, and usually only 2 go bad.  I have had luck
soldering the 2 good ones out of a used box and making one good unit out
of 2 bad.
 
To test you can use a Mighty Vac or similar tool, hook it up to the
vacuum solenoid and check if for leakdown.
 
I had put up a page on repairing the units many, many moons ago,
including the slight differences from year to year but the hosting
company has long gone.
 
Different style boards and housings were used over the years, but the
solenoids are the same.  They're likely still selling rebuilts or
replacements, but if you want to play with it, find some used/defective
ones to play with if you're so inclined.
I have a box full of control units somewhere in my pile O Audi parts.
 
BCNU,
Experience is the name everyone gives to their mistakes.
 
On Tue, 8 Jul 2014 01:30:50 -0400 "mboucher70 hotmail.com"
<mboucher70 at hotmail.com> writes:
> Recently started getting some unusual behavior from the climate 
> control.  On A/C, with the climate control set to ?Auto?, air is 
> normally directed through the front and side vents.
> 
> Now, at random intervals, it will redirect all the cooling to the 
> footwell vents.  At other times it might redirect all the air to the 
> windshield vents.  Sometimes it corrects itself, but more likely I 
> need to reset it by raising the temperature then lowering it back.