99 ram 318/Auto 2wd. Runs and drives absolutely perfect. Problem is with the Air conditioning. Can be working perfect. Then you shut the truck off and crank it back up it may or may not work? Sometimes may go 2-3 days and work perfect, And sometimes will go 2-3 and won't kick on at all. When it's working it never shuts off like its low on freon. Low pressure switch has already been replaced. Didnt make any difference. Any of you moparts experts had this problem yet? Or give me anything to check?? Or can anyone perform a Exorcisms for me? LOL

Might be a problem with that rotary interior temp control on the dash. It is a vacuum switch and maybe it is leaking or has a loose hose connection. OOPS, I should have said the heat/a/c selector dial.

Trucks of that era are known for the blend door going bad. If that's the problem, there's a cheap fix for it. Plenty of info on the internet to help you decide whether or not that's your issue. If it is, don't allow someone to charge you piles of money to tear your dash out to fix it. There's a cheap, do-it-yourself fix for it these days...

Check and make sure the clutch is engaged when the a/c is on and not cooling. If it is on and not engaged, tap the front and see if it grabs and starts turning. If so, it's just wear - the air gap is too large. Cheap fix is to remove the nut and pull off the outer part of the clutch. you'll see a bunch of small shim washers. Just remove one until the air gap is roughly .040 and it will work once again.

Thanks for the replies. Its not in the temp control switch. The compressor does not engage at all when its being possessed. No power to the low pressure switch either. Guessing the problem may be ignition switch? Still lost and hate guessing.