If you turn on the A/C (working A/C), the car will run hotter than usual because of the power draw on the engine. If your car is close to over heating, always turn off the A/C and it will cool down, somewhat.
If the car is really starting to overheat, then turn on the heater at full blast hot and that will help cool the engine. If the discharge from the heater (on hot) is NOT hot, then you're
really in trouble because it means there isn't enough coolant to run the heater. Shut the engine off at once!
With your car, if the fan isn't coming on at the proper temp, then it's more likely the problem is the thermofan switch.
Thermofan switches are cheap and easy to install. They come in different temp ranges as well - I put a lower range switch in my car (so the fan comes on earlier - 75C).
Clark's has good procedures for testing both the A/C relay and the thermofan switches.
If I remember correctly, the A/C relay is #3 (blower).
