I noticed yesterday when I was sitting idle in my girlfriends driveway that the check guages light came on and the temperature guage was 3/4 the way up and rising so i turned the truck off. To make a long story short, the fan is not spinning, jus barely moving from the pulley on the fan belt. I know it is an electric fan clutch, and I am pretty sure that that this is the problem. However, because it is electric, it is expensive and if I install it it cannot be returned. I don't know if it can be anything other than the fan clutch but I am looking for other peoples opinions. Would you replace it, could it be something else? Any help would be appreciated.

Common failure on these trucks, the pcm controls the fan engagement, to be really sure here a bidirectional scanner can command the fan on high to confirm it failed. Lots of these have been replaced for this or the locked noisey symptoms.

I'd urge you to check your veh's paperwork & mileage on the chance you MIGHT still be under factory warranty. If not, and you're the original owner, GM factory customer svc and Chevrolet-GMC dealers have cooperated on many fan clutch failures to do replacements at anywhere from no $ cost to owner to 50-50.