If you want to see if the fan comes on, take a piece of newspaper and cover about 3/4 of the radiator--in front--this stops the air flow. It will heat up faster when the temperature reaches normal operating point on your gauge, etc., you will be able to tell by either looking or listening for the fan.

Take care to not let it overheat

Your air conditioning may be low on freon, but the pressure switch may be bad or a wire broken or chewed up by a hungry rodent.

 

The AC runs the secondary fan.