Which engine do you have?
Are you saying the radiator fan runs all the time, even with the ignition switch off, or is it just when the switch is on? Is the Check Engine light on?
If you unplug the two-wire coolant temperature sensor, the radiator fan will turn on in case the engine is overheating and the Engine Computer wouldn't know it. My guess is your fan only runs with the ignition switch on, the Check Engine light is on, and there's a diagnostic fault code set for the coolant temperature sensor. That would all occur if the sensor was unplugged, one of the wires is cut, or one of the terminals in the connector is spread or corroded.
Do you know how to read the fault codes?
Sunday, October 6th, 2013 AT 9:21 PM