Hello my fellow Yahoo users.

I am having an issue with my 1997 Pontiac Sunfire 2.4L SE.
My cooling fan will only come on when the AC is turned on, or when the car is just about to overheat. The car will get about 5/6'ths of the way up the temperature gauge before turning the cooling fan on and cooling down a bit. So it will not overheat, but I know that in the years I have had this car, it will not go past the halfway point on the temperature gauge, even with the AC off.

I have replaced the cooling fan motor in the past as it went bad, so this is not the issue. The cooling fan fuse is good. I swapped the cooling fan relay with the heater/blower relay as they were the same, and it still did not help. There is a coolant temperature sensor near the top of the engine. If I unplug it when the fan starts running when the car is overheating, the fan will turn off. I replaced this sensor, but it did not fix my problem.

I had thought cars had two sensors. One that tells the instrument gauge what temperature it is, so I know how hot it is, and one that controls the computer and tells it to turn the cooling fan on. I could not locate any other sensors though.

What could possibly be my issue?

Thank you!
Thanks for the answers everyone.

I do my own car maintenance at home. The coolant has been flushed several times. When I replaced the sensor it read differently at first, but eventually got up to the almost overheat. So it seems like that was not the issue. Could there be a fan switch sensor I'm not seeing? I looked all over my engine and can't find any other sensors.