cooling fan not turning on consistently

1998 CHEVROLET CAVALIER

170,000 MILES • 4 CYL • 2WD • AUTOMATIC

AARON

MEMBER
1 POST

my chevy cavaliers fan is not turning on consistently i have replaced the thermostat, cooling fan relay, radiator cap, water pump and finally the cooling fan itself and it still wont always turn on i would just like to bypass the relay and have it turn on whenever the car turns on

Jan 13, 2011 at 3:25 PM

SQM

✓Experienced Mechanic
6,383 POSTS

Hello,

It sounds like you might have an issue with the coolant temperature sensor.
That sensor sends signal to the ECM of when to turn on the cooling fan. If the calibration if off on that sensor it can send incorrect data to the ECM and the fan will not get turned on.

The coolant temperature sensor is located on the upper part of the engine on the thermostat housing (see diagram below).

You might find these articles helpful:

https://www.2carpros.com/articles/how-a-coolant-temperature-sensor-works
https://www.2carpros.com/articles/symptoms-of-a-bad-coolant-temperature-sensor
https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

I attached diagrams for your reference.

Please let me know of any questions.
Thank you.

Images (Click to enlarge)