What would make the cooling fans only come on when the AC is turned on ?
My car has 137000 miles.
My car has an automatic transmission.
Most Vehicles now have 2 separate cooling fans. One cooling fan is intended to come on when the engine reaches a certain temperature. The other cooling fan is intended to come on when the air conditioning is turned on. When the air conditioning is turned on the fan kicks in to draw air through the condenser. When air is drawn through the condenser it promotes a good working air conditioning system. This is a normal operation of the vehicle and I would not be concerned with this as a problem.