Today was the first warm day in over 7 months, and my first chance to check the airco in my 91 PA. It doesn't work. :disappoin Outside temperature was around 70, in the car at least 100. I put the climate control on the coolest setting and the fan does go on maximum speed - but the air it blows is just outside air of about 70 degrees.
All the vacuum operated flaps seem to work, the air changes direction when selecting the different options.
Or does it take a really long time before you get cool air or something?
Is there anything I can check? What could be wrong?

Today was the first warm day in over 7 months, and my first chance to check the airco in my 91 PA. It doesn't work. :disappoin Outside temperature was around 70, in the car at least 100. I put the climate control on the coolest setting and the fan does go on maximum speed - but the air it blows is just outside air of about 70 degrees.
All the vacuum operated flaps seem to work, the air changes direction when selecting the different options.
Or does it take a really long time before you get cool air or something?
Is there anything I can check? What could be wrong?

Visually locate the AC compressor on the motor. Have someone turn the AC controls to on and see if the outside hub next to the belt starts spinning with the belt around the
pulley with the belt on it.

If it doesn't engage at all, most likely low freon. Needs recharged.
If it engages and goes on and off quickly rather than staying on 30 seconds or more then off a while then back on, low freon.

Thanks for your reply, after reading up on the subject I realize there is nothing I can do to fix it and will have to take it to an airco service. The refrigirant is R12, but this has been outlawed for recharging. They recommend R413a as a substitute, rather then converting the system to R134a. Any opinions?

If you decide to do a conversion to 134a, you should follow this procedure; Click Here (http://autoacrepairs.com/134aConversion.htm) I have had good luck with Freeze-12 on old R-12 systems. Click Here (http://www.freeze12.com/) for more info. Freeze-12 is now an EPA acceptable substitute for R-12.

The AC was checked by a specialist.
The system had no leaks and was charged with R12. But the hub on the AC pump does not engage. He tested the low pressure sensor, which was ok. Then the AC pump was wired directly to the battery. The AC pump works and the defrosts vents immediately blew ice cold air.
He thinks the problem is electronical, but would be difficult to fix due to the complex climate control system in the PA.
What could be the problem?

check out the BCM (do your interior lights work?) if not thats what it is for sure.

Yes, the interior lights work.

Hello could any one send me pic of the little black box's under the dash board i had my climate control fix but now i only get air from the floor and windshield could any one help. i forgot i have a 96 buick park ave i have took the dash a loose and i hear air coming from a big black box it have two arms on the other side is a small black box and have wires coming out help please.

I have a thread that I posted similar to this. It would probably be copyright infringiment to post a diagram from a manual. I have some that I got from alldata. This is a complicated system and I did very well it auto heating & a/c when I took it in school but that doesn't really mean anything. That being said does it all ways go in defrost mode or blows out of the vents and then goes to defrost mode. Does the climate control display flash if so it could be many thing. Blowing thru the windshield and the floor is default mode.

But you could more than likely have a vaccum leak if its like that all the time. There is a hose that goes from the manifold to the intake to the firewall. Also check all your vaccum lines that go from the HVAC control on the passenger side to the actuators located under the dash on the drivers side.

One more side note. I was think vaccum leak on my system at first maybe it was a slight leak. But seems to be more likely the ambient air temp sensor malfunctioning even though it was in specs. I changed it out yesterday and seem to have no problems so far since I changed it out. The temp display would go crazy it would go blank and the go to centigrade and the go back to normal. I would have expected to have out of range temps. Hopefully this will solve the problem. If not I probably will have to swallow my pride and go to the dealership.

Hope you solve your problem :smile: