Bocatrip

My cooling system is fine and always operates at the normal temperature. My question is this........Are both radiator fans supposed to come on whenever the a/c is turned on? The fans will stay on continuously as long as the a/c is on. When the a/c is turned off, both fans also turn off. Is this the normal operation of the car's cooling system with the a/c? Thanks all.

rkw77080

The cooling fans operate as a pair (i.e. Not independently) and has 2 speeds. The primary control is by the ECT (Engine Coolant Temperature) sensor. Both fans will run at high speed once the ECT sensor measures 180°F. In addition, when the A/C is On, the fans will run at low speed if the ECT sensor measures below 180°F, and switch to high speed above 180°F.

Bocatrip

Thanks for the info. Both my fans as mentioned are always on with the a/c and are not excessively loud. Living in Florida, the a/c never shuts off. Just not sure without testing if they ever go to the higher speed, even in excessive heat.

rkw77080

So to perform the inspection as outlined above in the repair manual, start/idle your car first thing in the morning with A/C OFF and observe the fans are also OFF. Next, turn on the A/C and observe the fans running in "Low" speed. Lastly, unplug the ECT sensor (to simulate 180°F coolant temperature) and observe the fans running in "High" speed.

Bocatrip

Where exactly is the ECT sensor located? I'm sure disconnecting it should be done carefully as the plastic connector must be brittle and cooked from engine heat after 17 years. Is it the bigger black plastic connector to the left of the two grey connectors on the left side of the reservoir?

911LE

The ECT is located on the front coolant crossover pipe. It is just to the left of the throttle body. It's removed in this pic. It goes where the copper sealing washer is.