For you others out there that are thinking you have a bad compressor because it is locked up, there is something to keep in mind here. This compressor can be tricky to see that it's not moving. The center of the pulley will only move when the compressor is turned on/blowing cold air. The outside, actual pulley portion will still turn free on the belt while the center is sitting still. It's dark down there and hard to see if the pulley itself is still moving when you see the center section stop. Just want to make sure your not seeing the center of it not turning and thinking that your compressor is locked up. Could be an expensive mistake to make.

I can say from past expriances that The AC on my truck is one of the few parts I will not try to mess with... It can be a pain in the ass to mess with. You don;t ant to dump the freon out it to the air and then you have to recharge it... I can never get them working right (blow as cold as they should) without taking it to the shop... Big PIA.

You can replace the clutch on the compressor but if it's not turning at all it would almost have to be locked up. Compressor for my 98 1/2 ton was $250

Well, I replaced the water pump that was turning completely free and seemed just fine and the serpantine belt that had some minor cracks in it but nothin very deep and no glazing on it and between them it's fixed now.