I have a friend who owns a 2004 Chevrolet Tahoe with the 4.8-liter engine. He discovered, much to his dismay, that the belt that drives the air conditioning compressor is a separate belt from that which drives the rest of the accessories. He asked for my help when he needed to change it. To get to the air conditioning belt, we had to take off the serpentine belt.
The Serpentine Belt
To get the serpentine belt off, we had to remove the air cleaner outlet duct. We used a breaker bar and hex-head socket on the drive belt tensioner bolt to rotate the tensioner so we could slip the belt off. Once the belt was removed, we used the front frame rails to jack the truck up and support it on jack stands.
The Air Conditioning Belt
Underneath the truck, we had to remove the engine shield and then insert a ratchet into the hole in the air conditioning belt tensioner. Rotating the tensioner clockwise allowed us to slip the belt off the pulleys. On reassembly, we tightened the engine shield bolts to 15 foot-pounds and the bolts on the air cleaner outlet duct clamp to 62 inch-pounds.