Coupe quattro climate control weirdness

[SJ]

> From: "Horning, Zain A" <HORNINZA at alfred.edu>

> I have a 1990 Coupe quattro that has been experiencing some climate
control issues.  >
> Last winter, my climate control would occasionally "get stuck" and blow
hot air constantly, regardless of the setting.  >The problem seemed to go
away during the spring and summer so I forgot about it.
**** If your system is the same as my 90 100q, then the system is
electro-vacuum operated. Electronics control solenoids which open and close
vacuum valves. At the back of the control unit, is a large rubber connector
where all the vacuum lines are terminated. This area sometimes develops
vacuum leaks. I take the connector off, lubricate with silicon grease, check
for any damaged/cracked vacuum lines. If this doesnt do it, check the
connections at the other end.
I think the temperature control is operated by cable. Motor and gear
assembly . .under and behind the dash. You can remove that and watch how it
operates. Any problems will be obvious.

SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q