I have a problem with the dual temperature A/C on my 2004 Avalanche. The driver side air is blowing hot and the passenger side is blowing cold. I checked the compressor an it's working properly. What could be the problem here?

You need to check for low R-134a.
Post back high and low pressure readings at idle and at 2K RPM.
Also a good body capable scanner will test and show codes if a problem on the automatic AC/Heater system.
MT

Most times that condition is caused by low freon,whats happing is the
evaporator is only half cold because the systems low on freon..