Rear A/C Question

I have a 2001 Tahoe 5.3L I was wondering if anyone has had the same problem I am having? The front a/c blows really, really cold but the rear doesn't blow cold. I have taken the interior out in the back and felt of the rear evaporator and it feels somewhat cold. Could the front work fine and the rear not if it was low on freon? Even though they both use the same system and compressor? Any help would be appreciated.

I'm looking at a '98 manual, so take it for what it's worth. The rear A/C uses a "Thermal Expansion Valve" (TXV). It's in the low pressure vapor line just below the outlet to the rear evaporator. Another thing could be the temp control door in the rear plenum itself. Hope this helps.............Steve

To let everyone know, I did figure out the problem. It was the "thermal expansion valve" in the rear of the truck. The valve itself wasn't bad but there is tiny little screen in the valve, on the compressor side, that was plugged. You can take this screen out and clean but since I had already bought a new valve I decided to replace the whole thing.