Why wont the cooling fan run on 1993 mercury topaz?

Answer 1

There could be a number of problems. Start with checking if the fan is working. Unplug the wire to the fan and jump it with a good battery. Either pos. or neg. to either side. If the fan does not work, most likely the fan is defective, replace it. If it works, then make sure the power is getting to the wires. Check the wire plug to make sure it is clean. If this is good, with the engine at operating temp. use a 12 volt tester to see if power is being sent to the fan, if yes, then the fan really should work at this point, as per previous tests. If no power to the plug, then go to the fan sensor, just follow the wires to the sensor for the fan, and not for the engine temp. Unplug the sensor wire, jump the 2 wires with a paper clip, if the fan starts, then the sensor is defective, and just replace the sensor. You could do this first, but just make sure the fan does work by doing the first test. As long as there is power going to the plug at the fan it should work. If replacing the sensor, and the fan still does not come on, but the fan only works when you jump the wires at the sensor, then instead of spending a lot of $$$$$$$$$, just wire in a toggle switch to these two wires inside the car and operate manually. Hope this all helps.