I am having a problem with my air. When you first turn air on it cools really good, after driving say 30 miles the compressor will no longer cycle. I have checked all fuses and realys. fuses are good relays are good.

In the driveway I can run the truck for about 15 minutes and the compressor will quit cycling and air goes hot. I can rev the engine to about 2000 rpms and the compressor will start working again, but 15 minutes later the same thing happens.

I have tried jumpering the high and low pressure switches and it made no difference. checked the freon level and found it to be a little low, so I topped the system off. still blows hot air 15 minutes later unless I free rev the truck past 2000 rpms.

Sorry for this being so long, and thanks in advance.

Brian

 

Check the air gap on the compressor clutch- it should be close to .020... I think the limit is .027 or .030.. mine is currently over .040 and I have the same symptoms..

I've been told if you remove the clutch, you can remove shims behind it to close the gap up.. but need to get under it myself to see....

Gary S.

 

So what your suggesting is that the A/C clutch mechanism IS work, just NOT enguaging do to the LARGE gap between the clutch plate and compressor. Right ???

 

I've had a chance to work on my system on a hot day now, and I'm now thinking it's the high side pressure switch (it's connected to the pipe coming from the compressor going to the condensor)

it seems to me like there's a timer that will not allow the system to activate again for a set time limit once the high-side pressure switch is activated...

mine does not even energize the clutch once the high-pressure cutoff is triggered... I tested it..

possible causes are defective high-side cutoff switch, air in the system, or system is overcharged....

but you may want to take a look at your clutch when this problem is occuring- you can see if the gap is closed (energized) but slipping, or if the clutch is not being energized at all.. (the gap stays open)

good luck, I'm going to wind up evacuating & re-charging my system, so I'm sure any air is gone, and I know exactly how much is in there...

Gary