I have a 2003 Chevy Suburban owned since new. Recently I have noticed that the front AC does not get that cold unless I turn on the rear AC also. It also seems like if the rear AC is off the front will only get cool if I am moving. Any ideas about cause would rather fix myself. Any help is appreciated

 

I'm an expert on the automotive front, under the dash A/C, I have not had the chance to work on a Suburban with twin evaporators before, which I assume the back one uses an electric fan to blow the air across the evaporator. Since the 56 ounces of R-134A a Burb uses compared to the 36 ounces of R-134A a front evaporator only uses, means that there is no ducting to the rear, so my guess is that you likely low on your refrigerant, R-134A, and that your engine fan is not pulling enough air across the condenser fins, which is mounted in front of your radiator. With two evaporators to operate, your one A/C compressor and condenser have to work harder to keep your Chevy cooler, so logically, it would also reduce it's life-span as it's working harder, then a vehicle with only one evaporator to used to cool down a vehicle's A/C system.

Since you have an engine-driven fan with a shroud, is the fan operating properly? Perhaps the severe-duty thermal fan clutch is not working well, so when you drive, the air from moving flows more air over the condenser fins, which increases the cooling of your Burb'. At this point, it would be best to hook up an A/C gauge set and give me the pressure reading that you have, otherwise, I cant advise you further. At the age of your Chevy its easily possible that your A/C compressor is running down weak and might need replacement, but without some high and low-pressure readings, there is no way that I can help you out much further at this point in time.