2000 Sable overheats

DarkRed
every once in a while the temp guage moves toward the "H", so I shut the car off and wait. when I restart the temp is fine and it doesn't happen again for several days or weeks! I tried to figure out just how the radiator cooling fans work to see if they might be the intermitent problem, but they are very complex. Could it be an intermittent thermostat that sticks closed sometimes? I also notice that the air gets warm sometimes while the A/C is on; don't know if they might be inter related. I should add that I believe the car is really getting hot when the guage moves toward the "H" but I can't say for sure.

One more question, Should one of the radiator cooling fans operate when the A/C is turned on?

Actually, in most cases, both fans should operate with the a/c switched on. If only one is operating then test the other to see if it is bad.

I would suspect first the coolant thermostat, second the cooling fans' coolant temperature sensor/switch. Can also be a connector with poor contacts supplying electricity to the cooling fans, which also could make the fans shut off intermittently, even if the sensor switch is fine. With the AC on, the radiator cooling fans should be on.