Climate Control gone hot...

Dan Sinclair
Mon, 16 Sep 2002 14:39:49 -0700

Hi all,

Well, I violated Audi Rule #1 - if it's not broken, don't touch it, breath =
wrong, or look in it's general direction...

1990 Coupe Quattro, US Spec.

The problem:  My Climate Control suddenly seems to be pushing out abnormall=
y warm air when in the ECON mode.

I usually run in ECON most of the time, and have it set at 65-70 degrees.  =
This generally just blows cool vent air into the cabin for ventilation.

Long-winded background:

I was fooling with some stereo stuff over the weekend and did three things =
- one of which I suspect is related to the new problem:

1=2E  I ran some wiring under the dash, into the center console and to the =
stereo head-unit - located immediately above the Climate Control unit. (I c=
hecked twice to see if I knocked off a hose or wire - didn't look like it).

2=2E  While looking for a hole in the firewall to run a wire to the battery=
, I found that the intake area for the Climate Control blower/fan unit was =
partially covered with dead leaves and debris - so I cleaned it out, vacuum=
ed out the debris, and the air duct is nice a clean now.

3=2E  I found a vacuum line just in front of the battery that was disconnec=
ted.  I suspect I may have knocked it off myself taking the battery cover o=
ff, but I can't be sure.  Don't know if it was off prior or not.  It's conn=
ected now though.  It's a yellow vacuum line that runs to a small 'pot' dow=
n by the block, with a fuel line running into it.

Theories?  I did notice a two wire sensor near the blower/fan intake that I=
 cleaned up - is it possible that the leaves were blocking this sensor, and=
 my climate control is now working properly, where prior it was obstructed?=
  I have my doubts.  The other oddity was on a 60+ degree day, my 'outside =
temp' was reading 31 degrees (way off...).  It's always been pretty accurat=
e prior to this weekend.  Is it possible one of the sensors just coincident=
ally died and is throwing off the temperature feedback - forcing the heat o=
n when it shouldn't?

I don't understand this system very well, so I'm not sure where to look.


1990 CQ