I had an overheating problem, not long after I got mine. Turned out that something was blocking the air from getting through the radiator. When removed, all was well.
Check to make sure that the fan comes on, when the A/C is turned on. You could always apply 12v to the fan, to make sure it comes on. Don't change it, if it isn't the problem. From what I've read, so far, I don't think you've jumpered the fan circuit to test operation.