there is 2 fans. one is a radiator fan (turns on only when the engine reaches a preset temp usually 215 or so) the second fan is for the ac condensor (turns on only when the ac is on). the radiator fan is controlled by the computor. there is a relay and a fuse in the circuit. its fuse #47 and it is a 20amp. check the fuse. if the fuse is good, try and power the fan with a 12v supply @ the fan itself. does it only over heat at idle or does it over heat when you drive?