When I stop at a light for justa few minutes the engine temp starts to climb. As soon as the car gets underway it starts to cool down again. I beleive there is an electric fan on one of the front (right?) radiators (car has 3 radiators; left, front and right) but I don't know how to test that it is working - I do not heara fancoming on. Problem is worse in hot weather. Is there a relay / temp sensor somewhere I can check?

Thanks.

 

Fuses Row C 8 and RowC 10 control your 2 key fans which are 2 speed units Low Speed at coolant temps of approx 96 Deg C and Hi Speed for +102Deg C. Both 30amp fuses.
Start there. Regards Big Bob

 

I checked the fuses and the relays with a meter and power supply - all are OK.
I jumpered the relays and confirmed that the fans turn on and operate normally.
So now it appears that the relays are not being actuated.

Does anyone know where the temp sensor is that actuates the fan relays?
Is it the same sensor that drives the temp gauge on the dash?

Thanks.

 

Hi
The engine temperature sensor is made up of 2 NTC resistors in the sensor housing and is installed in the coolant duct housing.
One sensor resistor measures coolant temperature and the signal goes direct to the temperature indicator in the instrument clustert.
The 2nd sensor resistor is used to inform the ECU of coolant temperature. This signal is used by the ECU to do the following:
1) recalculate the fuel injection schedule during warm up.
2) richen the fuel/air mix during starting.
3) determine ignition angle (advance retard etc) during starting
4) control the radiator fans

Regards Big Bob

 

Hi Big Bob,

Thanks for the info. I would have expected the fans to kick in as soon as the car stops at a light as there is no longer any air moving through the radiators. I supose the second sensor could be bad but the car starts and runs just fine. The manual I have suggests that the radiator fans don't kick in until the temp rises quite a bit above normal?

Do you know what controls the fan on the rear engine hood? I don't hear it kicking in either.

 

Hmmmm....now you've got me wondering about this too!
Come to think of it, when I park my 2001 911 in the garage after driving home from work I have never heard a fan coming on, front or back.

Normal temp readings though I guess....whatever normal is....it's never gone into the red zone and I never thought about a fan until I read this.