Why won't the radiator fan on a 1999 Jeep Grand Cherokee kick on if the motor will run fine but it isn't getting the signal to turn on?

Answer 1

In cooler weather, it will take the fan a lot longer to be energized. One way to do a quick check, is to turn on the A/C. All the fan(s) should turn on with the A/C running. Some people call an engine a motor. So I am not sure if you are talking about the fan motor or the engine. If you are saying that the fan motor was checked and is good then the Thermal sensor is bad, or you have a loose or disconnected wire. The fan comes on at a predetermined temperature when it receives a siganl from the relay. you'll need to check the fan switch located on the radiator or there abouts, when you jump it the fans should come on...also make sure there is power to the switch...if theres power, and you jump it and they don't come on..its most likely the fan motor...if no power, there may be a bad relay or fuse...good luck also... everyone should have a manual for their vehicle, and a professional shop manual should be available at the library in the reference section--you can make copies of the necessary information...good luck :)