Problem began slowly as the summer warmed up. Got worse to the point couldn't drive more than a couple of miles before overheating. Changed the thermostat as it was sporadic at first. Didn't help at first but then learned I had to bleed off the air. Now it is a little better but still over heats when loaded. The fan was turning but you could stop it while running by hand. I assume this is the clutch and have removed the fan to replace the clutch. One aux fan runs when the a/c is on but neither run when engine heats up. Why would one run with a/c but not when hot? checked fuse and it's good. Any suggestions where to go from here?