So last year the AC stopped working in the truck and I am finally fixing. I had someone look at it and they said the compressor was bad. I just changed it out and now i have pretty cold air in the front but in the rear I am blowing nothing but warm air (and it's not the damper door, it does blow HOT air when I turn the heat on).
I have never changed a compressor and didn't realize to change the orifice and the dryer when i had the system discharged and may end up emptying system and doing that because I am sure it needs done.
With that said, here is what I have and again I am a novice at AC systems.
Both lines going to the condenser on the high side are warm/hot. I assume this is correct as that is the hot air being cooled through the condenser.
All lines going to the rear are warm. Possibly bad Expansion valve in the rear but I would assume at least one of the lines going to the back would be cold?
I have attached pics of the lines up front that are cold and the ones that are hot. I don't know the layout of these real well but there are a few lines I would assume should be cold that are not.

Any help would be appreciated. I think this weekend I am going to drain the system and replace the orifice,dryer and the expansion valve. Do you all think that will fix the issue or do you think I have something else going on?

 

Yes, that would be the place to start. They are probably plugged. You may need to flush the lines.

 

Rear TXV is the most likely issue. Debris/trash in the system may be the issue, but more common would be a failed powerhead, (the external silver disk) on top of the rear valve. When you open the system up again and remove the front orifice/strainer you know how much trash may be in the system. The front system is typically run more than the rear, therefore the front strainer will catch most of and debris and keep the rear lines somewhat clean.

 

All good now. I did have the system evacuated and replaced the orifice, dryer and expansion valve. The expansion valve is definitely what was causing the warm air in the back. Did a check on low/high pressure side and everything is right where it needs to be. Super cold air front and back now.