Fan Clutch
 

Any way to test the fan clutch without a scannet

I know if you unplug the oil temp switch the fan will be on full force:w2: no doubt about it when it is on, sounds like a Mack truck when it is pushing that much air. I don't think mine has ever kicked on full force, even when towing 15k in 105 degree weather. the cooling system on these trucks is pretty stout and not worked very hard.