Outside air-flap, yes, climate control again

[Tak Cheung <tcheung@gandalf.rutgers.edu>]

I would like to know under what conditions the outside air-flap opens ?

My recent '91 100 (regular) seem to have it's air-flap closed all the time
and I'm having defrost problem in really cold weather.

If I pulled it open, and when I hit OFF on the climate control, the flap closes
properly.  However, I have yet to see the thing opens on its own (mind you the
temperature here have been mostly under freezing).

So, is there a test code I can read from the control unit to see if the 
flap is working as it's supposed to ?  Also, how to check the inside temperature
sensor ?  I have a feeling if the temperature sensor isn't working, the air-
flap may not open on its own.

The car is still under Audi's 1 year warranty and 2 year drive train warranty,
so I want to demontrate to the dealer the thing is not working properly before
they give me that "it works fine" answer.

Many thanks,

Tak Cheung
'91 100
'87 Acura Integra (trading in for a Saab soon :)