[Red_Mystang]

Hey does anyone know what sensor i need to replace if my hi speed fan isnt working? My low speed fan works and then when it goes to kick on hi speed the fan just shuts off and my car ends up overheating after a period of time if i just sit and idle. Can anyone tell me what controls that so i can replace it because it isnt working. Thanks

 

[TheRoadWarrior]

I'm too lazy to check out your profile, your car is not in your signature, so I'm going to give you a generic reply: fox body and 94-95' = replace your ECT or check the fan and test each speed with a test wire. For 96' and newer: ask someone else because I'm a dinosaur and only deal with old stuff.

 

[stars]

The power train control module (PCM) controls the fan via two relays in the bussed electrical center (BEC). Maybe a bad relay for the high speed side (or a failure in a wire harness)?

Ford Service Manuals - Wiring Diagrams

There's a temperature sensor in the thermostat housing that provides engine coolant information to the PCM. If you're going to replace that you may as well shotgun the job and do the thermostat and housing while you're at it.

http://www.allfordmustangs.com/forums/2005-2010-v6-mustang-tech/206857-2005-v6-mustang-thermostat-housing-replacement-how-pics.html