My 7331 '84 has been doing the same thing. I have replaced the water pump, the thremostat, and the fan clutch was check by a shop along with system pressure. I checked every fuse in the box---all looked good. I will replace these anyway and see what happens. My aux fan never runs either--even with the AC on. It used to--it was loud! Are there any releys attached to the critter? Anyone replace one that was shot? How much work am I in for if the fan unit itself is a goner.