the coolant fan relay, the coolant temp sensor. and or the coolant fan motor itself.
You want to check for fault codes stored in the ECM, if any.
check the relay first. below is diagram of the fuse box under the hood.
There is a coolant temp sensor for the ecm, there is also one for the gauge. and a coolant fan temp sensor. if all are good.
if the fan comes on with the a/c on then the ecm is good and commands on, the relay is good, and the wiring between the relay and the fan motor is good. it has got two be in the sensors.
i did not know there was 2 switches i will be replacing both of them. the question is will it be expensive.