Pontiac Repair: A/C and Blow Issue in 96 Grand Prix, vacuum leak, dash vents

Question
I have a 96 Grand Prix, last winter the blower stoped blowing out the dash vents, heating and A/C however still worked but blew out the Defrost and floor vents only no mater what the controlls where set to. Shortly after that the A/C clutch failed and I had to replace the compresser. After that the same condition continued with the blower and vents but now no A/C. Thinking it was a bad compresser I replaced it again with no change. I have gone on and replaced the fuse and relay with no change. The system has the perfect preshure and I don't see an obviuse problems. I am not sure but I think they are different unrelated problems. Can you give me some suggestion on what to look at next.

Answer
Hi Michael.

I think you have 2 different issues here. You may have an issue with a mode door inside the car where one of the doors is binfing up or that actuator may be bad for the mode door. You could have a vacuum leak going into the car causing the air to come out the defrost mode only. Now as for the a/c compressor you fould have a fuse that blew causing the compressor not to run. You could have a pressure sensor bad in the a/c line not telling the computer there is enough or to much pressure to run the compressor.  You could have a issue with the hvac control head that it's not giving the computer the signal to turn on the compressor... with out the aid of a scan tool this is hardto find. with a scan tool you can see if there is a/c request from the hvac control head, you can see the pressure reading from the pressure switch and also see if the computer is commanding the a/c relay on. good luck :)