Hello all, I'm new to these parts. I got a hold of this truck dirt cheap. It has very low miles and has spent much of its life sitting under a tree. The A/C was not cooling real well, so I charged it up enough to make the compressor stop cycling off and and on, about 40 psi. I later learned that Dodges don't like that high a pressure. Is that true? A secondary issue is that while the A/C is running the air flow will switch to defrost for about 12 seconds all by itself, then it returns to the vent. Any ideas?

 

Search through the numerous a/c threads here lately. They may give some insight. Im not that familier with it.

The vent issue would be "wild vents". Search that term and youll have all you should need. (Hint) its a vacuum leak.

 

Hey, Your vent issue is likely due to a vaccum check valve. There are 3 near the back of the block on the passenger side. They are around $12 ea. Had the same issue and this was the fix.

 

Check the wild vents thread in the faq section for the vents switching.

Low pressure is dependent on ambient temp. Should be a chart on the side of the bottle, just compare temp, with what pressure should be. Adjust accordingly. If necessary....

 

And if there is NOT a chart on the side of the can, you can google it or check the service manual in the FAQ/DIY section. Ambient temp has a greater effect than most people realize. you don't just charge it up untill it won't hold anymore!

 

Ummm...the a/c compressor is supposed to cycle.

These trucks have a CCOT system.