2000 Ford Focus • 4 cylinder FWD Automatic • 142,000 miles

I have a 2000 ford focus that is overheating when I idle. I have replaced the thermostat, and its not the sensor because it shows my car is overheating. The car wasnt overheating as long as I had the heat on 4 on the inside of the car, but then the heat and a/c quit working. Could this be the resistor or is it that the radiator needs flushed. Neither have been changed or done since I bought the car about 4 years ago?
March 26, 2011.

So when the car is overheating is the radiator fan running?Also the inside blow fan doesn't run on any speed?Do you have a multimeter to do some testing?

Mar 26, 2011.