Cooling Fan or relay

I have a 2000 Dodge Caravan SE which runs hot when I am stopped and idling for any length of time. When the temp gage rises and it starts to run hot the A/C starts to blow hot air until I start driving again and the temp gage returns to a normal operating temperature. I've been told it may be the cooling fan relay. I have noticed that both fans do run intermittently so it appears they are good. I've been unemployed two years so resources are very limited and can't afford to pay labor costs if I can do the job myself. Any help is greatly appreciated in diagnosing my problem.

By the way, I did change out the thermostat first and it didn't resolve the problem.

Thanks,
kkinamo1

Start the car and turn the a/c on. Does the cooling fan come on?

Thanks for your response. No the fans do not come on immediately when the car is started.

Nope the fans are not designed to come on immediatly after starting the engine. I have a '91 Caravan and it has two separate fans one for the radiator and one for the A/C. The radiator fan should come on when the temp gauge reaches about the midway point on the gauge, (or slightly above). I recently had a similar problem, and what I had to replace was the coolant sensor, it was located in the thermostat housing right next to the thermostat. It had been working intermittingly and had caused lots of troubleshooting problems.
The A/C fan should come on fairly shortly after turning on the A/C, same time or shortly after the A/C compressor cuts on. If you have just one fan for both, then it should come on with the A/C regardless as to the engine temp.

sounds like a temp sensor on engine or low coolant. the fact that you said " both fans do run intermittently so it appears they are good " tells me the relay and fans are good. The temp sensor tells the relay to close to provide voltage to the fans . however , the coolant can be low enough causing the temp sensor will not work. do not rely on the plastic bottle on the side, you must open the radiator cap to fill it ,after the car cools down . ps yes the fans should come on when the ac system is runing.

Here's how the fans work.
http://www.automotiveforums.com/vbulletin/showthread.php?t=909708

Hey thanks everyone, the fans worked fine and it turned out to be the radiator needed replacing.