So my AC stopped working a few months ago. The compressor would cycle on and off quickly. I hooked up the gauges and it looked like it was low so I tried to add refirgerant. It barely took half a can, but the pressure came up enough that it worked. Now, it is back to cycling. I hook up the gauges and the low pressure side is almost at zero and high pressure is around 100psi. I open the line to the refrigerant and the low pressure side jumps up to around 100psi and the high doesn't change. It will not take any refrigerant at all, and the compressor will not turn on even with the 100psi low side pressure. I put the jumper back in to turn on the compressor and the pressures do not change at all.

I am thinking that it may be the compressor, but until I try to add refirgerant it seems to work. I can watch the pressure build on the low side and it will kick on untill it drops to about zero psi on the low side. The High pressure fluctuates very little.

 

sounds like a compressor to me...

 

I am thinking it might be the compressor. It probably didn't help sitting upside down for a while during the plenum replacement, but I hate to replace it not being sure. I don't want to throw away $250 on a guess.

 

So find an a/c shop that will look at it and give you a free system checkup. I see them advertised all the time. Just make sure you tell them they don't do any work without your consent. If you can't find one for free, I'd say paying $39.95 for a system chechup would beat paying $250 for no reason.

 

I had the same problem on my New Yorker, and you won't believe what it turned out to be. My problem was the Expansion Valve (a $15) that caused the exact same issue as what you are describing. Of course to take it out means you have to lose all your freeon, but in the end, I think it is still cheaper guess that route than replacing a compressor. I don't think your compressor being upside down for long affects anything.

Let us know what happens.

 

Looking at the manual it seems it could be any number of things. Compressor, Evaporator, clog in the line, etc. I wonder how good a shop would be at diagnosing the problem correctly or if they will just go the route of replacing parts until it is fixed.

 

Does the truck not have an expansion valve that sits right in front of the expansion valve? On the New Yorker, it bolts up to the expansion value under the hood and the AC lines connect to the expansion valve.

 

You wont believe this, I had same problem and took to ac shop and couldnt find anything wrong but would still cycle. On a whim we checked codes and it threw a transmission speed sensor code. The ac guy cleared the code and all is well now with ac.

 

You might check to see if your vehicle has what dodge calls a orifice tube. They too have been known to plug up causing symptoms such as yours.