I have had my car for about 6 months. I tried the air conditioning, and found it did not work. So, I took it to a local air conditioner man, and he charged it up. In the process, at no time did the condensor/radiator electric fan come on. I do know the fan will run if the motor heats up while idling and then shuts off. What can I check to see why the fan does not run while the air condtioner is on?