Re: '93 90 CSq: Ventilation/climate control problem - fogging

[Elliott Potter <epotter@abraxis.com>]

> [...]
> The major symptom is fogging of windows when the temperature gets close to
> freezing.  In the winter months I run the climate control on full AUTO.
> The recirculate and A/C lights are not on.  I see the normal fan motor
> start on warmup and the motor slows when the target temperature is
> achieved.  The outside air temperature gauge is behaving properly.
 
This is an Endearing Audi Feature.  If it's too cold outside, the A/C
compressor doesn't kick in.  If the A/C compressor isn't on, you can't
use the recirculate.  I'm not quite sure of the reasoning behind either
one of these.....

> Another interesting symptom is that the A/C behavior is erratic.  Sometimes
> I can get the A/C to come on, other times not.  Occasionally, the A/C will
> come on at start when it was not selected previously.
 
See above--it's dependent on the outside air temperature.
Having said that, I fought for 4 years with my dealer before they
finally looked at a TSB on the A/C--it's on your ALLDATA CD, title "A/C
Compressor Intermittant Operation" or something like that.  Don't assume
that they've read it or even know about it, my dealer hadn't.

> The recirculate button does not cause the recirculate light to come on.
 
That's because the A/C compressor isn't on.  Recirc. doesn't work unless
the A/C is on.

> Other useful information:  this summer I was having problems with warm air
> from the vents when the system temperature was set to LO.  The shop
> replaced the actuator for the warm air door, but it didn't seem to help a
> lot.  
 
This sounds a lot like the TSB mentioned above--if the car has been
sitting out in the sun all day and is very hot on the inside, the A/C
compressor won't come on (and the little "snowflake" icon won't
either).  As the inside temp. of the car cools down, the A/C will come
on all by itself.
If these are your symptoms, PRINT OUT THE TSB and shove it under
someone's nose.  This isn't related to your cold weather problem, but
you should have it fixed.  Also have it fixed for free--the bulletin
came out in 1994, if they haven't fixed it yet it's their fault,
especially if you've complained about it before.

> The car is missing the large under-engine cowl.
 
You mean the big plastic thing?  That's there for a few
reasons--improves aerodynamics (I think, this may be wrong), protects
the engine/fan belts from objects you run over (i.e. sticks or aluminum
latters, etc.), and shields some noise.  If you've only had the car
serviced at one place, I'd go bug them about it.

> Any suggestions?  The AllData CD is useless for this car.
 
Yea, basically it is except the TSB's did turn out handy.

HTH!

Elliott

93 90CS whose airbag may inflate at any moment, causing "loss of control
of the vehicle" !!!
But at least the A/C is fixed....