My daughter Brenda has the opposite problem with her radiator fan, it won't run at all. First we checked the fans, they run with 12 volts, both of them. Have changed the fan unit on the drivers side of the radiator, at about $125.00, still won't come on. Changed the A/C relay inside the fuse box next to your left foot, changed the thermostat, and unplugged the temp sensor close to the thermostat, and the fan still won't come on. However, when she unplugged the battery, and plugged it back on, the fans would come on with the A/C running, then after a short run, the fans go off and will not come back on, and then the motor over heats and you must shut it off.
Has anyone had this problem with their radiator fan motors and managed to get it fixed?