Coupe Quattro 90 air conditioner question.

[marks@corp.cirrus.com (Mark Sobrepena)]

I have an  90 Coupe Quattro with an air conditioner that does not want to work. I've taken
it to the Audi Dealer and they can't figure it out. The symptoms are as follows:

1. There is no cool air and the air is as hot as the vent (economy).
2. If there is cool air (setting LO)  it goes out slowly after <15 minutes. Usually preceeded
    by a blast of humid air then vent air.

The dealer has recharged the coolent and replaced the thermostats. Their answer is
"I don't know" or "take it in again".

Any similar problems out there....