Is the cooling fan supposed to operate when the A/C is on? How hot must the engine get before the fan turns on?

All the vehicles I have one fan is operated by temperature the other fan comes on when the air conditioning is turned on.

the fan I am referring to is the main engine cooling fan. At the radiator. Thanks.

The fan comes on whenever you have the A/C on. There are two sensors that measure the temperature of the coolant. One sensor operates the temperature gauge in the instrument cluster and the other sensor turns on the fan. If the sensor for the fan is bad the fan will operate all the time even if the A/C is turned off. The radiator cooling fan will come on when the temp gauge gets just to the right of center.

disconnected the temperature sensor that goes to the pcm and the fan came on, so I guess it does work afterall.....