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

[Chris Newbold <cnewbold@transarc.com>]

Steve Peterson wrote:
> 
> 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

...
 
> 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.
> 
> The recirculate button does not cause the recirculate light to come on.

In full auto mode, the A/C compressor will run (and the "snowflake" icon
will appear on the LCD) when the outside temp. is > ~35F. Once the temp.
drops below this point, the compressor is automatically disengaged (and
the "snowflake" no longer appears).

If the compressor is not running, recirculation mode cannot be
engaged.

That's how the system is supposed to work. If you're seeing eratic
compressor operation with temps. > 35F, there's something wrong.
No compressor on cool, damp days can easily result in fogging...

One place to start would be to pull the codes from the CC computer
and see if it thinks anything is amiss.

> Any suggestions?  The AllData CD is useless for this car.

I share your sentiments on the AllData CD for this car... It does,
however, have the procedure for getting codes from the CC computer
and a table for their meanings.

The information is actually contained in a TSB for the CC system.

If you can't find it (or don't have the TSB module) let me know
and I can give you the procedure...

-Chris
1993 90CS ~62,000mi