View Full Version : AC Compressor doesn't engage

07-27-09, 07:40 PM
No AC on my 72 Fleetwood. The compressor won't work and won't even click - fuse is OK, but no power to the compressor. I need to get the AC working - fan works, all selections seem to work, but no compressor. Need to check this first, I have R12, but don't know what to do next.

Suggestions please ????

07-27-09, 09:52 PM
there is a pressure switch that needs to be jumped
when re filling, look near the fender well, on the a/c lines you should see a switch with two wires/terminals, unplug that and make a jumper wire
that should turn on the a/c clutch, and allow the system to take a charge
when the system pressure drops below a certain point it shuts off the compressor to avoid damage

08-02-10, 12:46 PM
Does any one know where this switch is on a 1991 Brougham? I think I need to do the same thing.

08-02-10, 05:17 PM
On the 91, the switch is screwed into the accumulator. Big silver can on the firewall on the passenger side. You unplug the connector, and jump across the terminals of the plug you just disconnected. Of course, the car needs to be on with the AC on for this to work. Only do this for a couple of seconds to confirm function of the compressor. Once you verify the compressor works, you need to figure out why your R12 leaked, fix it, vacuum, and fill.

On the 73, I am not sure the jumper trick will work. It was in the early 70s that GM went from a system where the compressor ran all the time (when AC was on) to a system where the compressor cycled. You should be able to find out which one you have easily. You can convert from the early system to the more efficient cycling one easily with a few parts.