Ny Cooling Fan Is On All The Time.

[bluemippy]

I have a 2008 focus st and I have noticed that my fan is on all the time whilst the engine is running my temperature gauge is showing normal. I have checked all the fuses and they are all ok, I can only assume that there must be a sensor some where on the car has anybody else come across this? or know where the senor is located?

[AdeMk1]

It will either be the engine temp sensor (the ECU will set fans to constant as a failsafe if no valid signal is being received from the sensor), or if you have the heater set to windscreen I believe it automatically turns on the AC to aid demisting in which case it will be the AC fans you can hear.

[iantt]

has it just started to play up, have you checked it with aircon switched off and heater fan off?

[bluemippy]

I have had a dianogstics test done today and it came back with fault code po111, now search time on google

[AdeMk1]

Intake Air Temperature (IAT) Sensor fault. Could be your problem, that and the Coolant Temperature Sensor (CTS) work together and should have the same readings.

[south_bound]

You don't say if it is petrol or diesel but I had that happen when the DPF was clogged and the car was trying to regen all the time. Then I noticed it again when the coolant level was down below the min mark on the tank so maybe there is a sensor which reacts to insufficient coolant as a fail safe? Anyway, ripping out the DPF solved the first point, topping up the collant seems to have solved the second one.