I need help. I have a 1998 Ply Voyager with a/c issues. The a/c works when it wants to. When the unit is in the off postition it still blows cold air only when the van is moving. The a/c button will light up when this happens When the unit is on it will sometimes blow and then shut off. What can be causing this???

With the switch in the off position and on position, apply up/down left/right pressure with a small screwdriver inserted well into the switch cavity. If the A/C turns on and off replace the A/C switch.

Thanks for the suggestion. I did try it and it didn't do anything. Would there be anymore suggestions?

Ok the switch appears good. Something is powering the A/C clutch relay on when it shouldn't. That's the only way the A/C will turn on or off. Power is always at the relay. It only turns on when a ground is supplied. I got a hunch you never see these problems when the van is sitting in the driveway. Road vibrations are doing it. Have you tried tapping/wiggling the A/C clutch relay on the Power Distribution Center (PDC) and the PDC itself and watching the clutch to see if it will engage/disengage. Next try swapping the relay with an identical relay somewhere else on the PDC or buy a new relay.

I appologize if I'm getting too basic but, the clutch is part of the A/C compressor. It's what transfers the spinning action of the belt to the piston in the compressor. The compressor is mounted on the passenger side of the engine and the clutch is the metal ring just outboard of the pully/belt. When the A/C is off the clutch shouldn't spin. When it's on the clutch spins.

Beyond the relay there's wiring, a pressure transducer, and the Powertrain Control Module (PCM). I'm a little fuzzy here so if I'm wrong I hope somebody will correct me. The A/C Pressure Transducer is part of the compressor (I think) and senses the pressures in the system. If the pressure is to low it won't allow the PCM to apply a ground to complete the circuit to the clutch relay. This prevents the clutch from engaging and destroying the compressor due to lack off lubrication from low or no freon pressures. If the transducer detects good pressure it allows the PCM to complete the ground to the relay and powers on the clutch/compressor. If there is an intermittent failure in that circuit, you see it as intermittent cool air.

For now check out the relay. That is the most likely point of failure. Cheers!

Well I want to thank you for all your suggestions. It appears to have been the relay switch for the blower fan. I don't how or why. I had my neighbor looked at it he said if the blower not working would cause the compressor to kick of too. But it seems to be working fine know.

Well I guess more specifics would have helped. The important thing is your headache is gone. Best wishes.

BTW - If you or the neighbor changed that blower relay...concider yourself bonified shadetree mechanics. That relay is a B!@#$% to get at. Cheers!

Guess what it was working fine than just stopped ao I guess it was not the relay.