Have an 86 Gll turbo. Replaced all the vacuum lines going to the vacuum canister. Replaced the water cork because it was sticking. Ran the self diagnostic test and everything worked. The problem I'm having is the water cork one gets vacuum during the test. So there is no real change in vent temperature. PO gutted the ac system, that might be my problem. Is there a way to trick the climate control to believe it still have AC?

 

doubt your water control valve is sticking it is just a very simple butterfly valve. I have similar problem. during the summer I just run vacuum direct to the water valve and then reconnect in winter when heat may actually be needed. a solution I am going to try is to run 12v to the solenoid on the vac tank so you always get no heat because vac is at the valve. I'm going to send the 12v via the old switch for the headlight washer so I can turn it off and get heat in the winter.