I have a 2011 F150 3.7 and at start the fan runs at the highest speed. I was told that I need to replace the Engine Temperature Sensor. I cannot find the sensor. Ive been told its under the intake manifold. Took that off and no sensor. Ive been told its on the rear passenger side of the motor, to go thru the passenger side wheel well. No sensor there. There is a sensor located on the drivers side on the bottom of the motor behind the alternator but the sensor that I bought doesn't match the connector. Any help???? Thanks

 

It's pretty unlikely that the CHT would cause this issue without causing other issues, namely fault codes and a check engine light. This is a PCM-controlled cooling fan system. The fans can NOT operate unless the PCM tells them to, barring things like a shorted relay or wiring issue. If the sensor were defective or malfunctioning, then the PCM would flag it.

Before doing anything else, check for fault codes and, if necessary, check sensor operation with a scan tool. This prevents wasted time, money, and skinned knuckles.

 

I have no codes and the fan is running constantly at high speed from the time I start it. Im annoyed. This shouldn't be that hard. And any search I do on this engine gets me links to the 3.5 and the 5.0 which do not help at all. Thanks for the response though.

 

I seem to remember other threads here about this issue on the 3.5 and 5.0, what fixes it is a computer reflash with an update. Research TSB's.

 

Scanning for codes isn't enough. You also actually have to go in and look at the data to be certain whether or not the CHT is working properly (or not). Since there are no fault codes indicated, I's probably not a sensor issue.

If you just want to replace the sensor anyway because you have too much time, money or skin on your knuckles to be bothered to do complete diagnostics, it's mounted on the rear of the passenger side cylinder head. I've heard it's best approached from underneath on some of these engines. YMMV.