AC Problems?

I have a 95 Sub with front and rear heaters/AC. The front AC starts out cool than goes to warm then cool . . . it fluctuates while the rear AC stays nice and cool ALL the time. A new compressor was installed last year (just before I bought it), 134A is reading 45 lbs on low side (good pressure). I read in a previous listing that this type of problem is associated with a bad Temp Control Actuator so I changed the front one over the weekend. It started out great but after I stopped the car and restarted it . . . it went back to the same inconsistancy (cool then warm than cool only in the front AC). It is HOT in Colorado so any assistance with this problem would be GREATLY appreciated . . . thanks! Could it be the Temp switch??

I having a simular problem w/ my ac in my 93 Suburban, but It always stays warm up front and simi cool in the rear. The one thing i did notice however, is that the clutch on the compressor only stays engaged for 30 second intervals, breaking for about 20 seconds. When i unplug the switch the clutch doesn't turn on at all, obviously. So I'm wondering the same thing if it can be my switch. Not that this test the sensor, but it seems like that's the only thing that controls the clutch engaging One other thing, when i turn the engine off i can hear the release valve releasing pressure. I believe this has to do w/ the compressor not staying on while the ac is activated at the controls. Also i can feel the tubing to or from the compressor and its cold. This vehicle has been converted over to R-134.

I can use some advise as well, today was a 103 degrees and having a vehicle w/ working ac that i can transport my family around is a must.

FYI... I read a previous post and tested the low level switch on account of the post suggesting to test it and turned out that I was low on feon. So I recharged the feon and it works good for now..

check your expansion valve and orphice tube.

Where is this located and how do i check these items.

The expansion valve is under the right side panel in the back of the truck,
replacing this one is a pain cause after removing the panel you have to deal with the air ducts that have screws in places where you can't easily reach them. I actually cut my ducts and then resealed them with silicone.

As for the orphice tube I'm not too sure, my front A/C system is always done at the dealer because it's under lifetime warranty, but my rear A/C system isn't, so I do it myself. But I had the same problem you had (cool in back, warm in front) I had the dealer replace the front orphice tube, this solved my problems. Also I have a 95, seeing as how the 93's originally used R-12 the piping may be different, you should check out a Chilton to find the orphice tube.

Good Luck