I have a 2004 F250 6.0, the fan clutch runs way to much. It locks in at the start of driving before the engine ever gets heat in it. I keep getting a faulty module code, this has to be it! Due to the fans running, not to mention loss of power and fuel mileage! Can anyone tell me if the fan clutch has a sensor or control module that activates it?

 

My understanding is that the PCM controls this through the ground wire of the clutch. I would check if you can spin the fan by hand to determine if it’s a mechanical problem. There are electrical tests you can do like unplugging the fan, and checking ECT sensor through FORScan. @bismic is pretty savvy with the controls and wiring side of this platform. Perhaps he can chime in.

 

Well here is some background:

Engine temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that you will see some variation in engine temperature as it correlates to fan operation. The operation/description of the FSS (Fan Speed Sensor) from the PC/ED manual has a fairly good explanation as to how the system "thinks". This is not your traditional engine hits temp X and the fan clutch locks up. The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor sensor inputs and control the VDF speed based upon engine coolant temperature (ECT), engine oil temperature (EOT),transmission fluid temperature (TFT) and intake air temperature (IAT) requirements. Also, the air conditioner high side pressure switch will cause the fan high speed to activate (ACP V). When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF. At least one person has seen the factory gauge go from normal to the "red" quickly. It happened around 240 degrees F.

We need to see data for the parameters that affect fan operation. Getting these values at KOEO is a good start. Make sure the air conditioning is off.

ECT
EOT
TFT
IAT1
IAT2

After posting the data, I would like to see a picture of the fan clutch wiring connector.

 

ok, i will check into all these and get back to you guys, Thanks!!

 

New to you truck?

If so, the previous owner may have installed a 7.3L fan instead of the electronically controlled one.

 

No sir, i have owned the truck for 10 years and replaced the fan clutch about 3 years ago

 

Thanks for the clarification. Typically, the failure for these is not working, not overworking. The controlling "blue wire" that goes to the PCM may be grounded somewhere.

 

Sensor failure is the most common reason for fan overworking.

 

When my EOT sensor failed, my fan ran 100% of the time. I can see that happening if the ECT sensor goes bad too.