overheating, cooling fans not working

2001 BUICK CENTURY
142,000 MILES • 3.1L • 6 CYL • 2WD • AUTOMATIC
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ZACH MUSICK
  • MEMBER
  • 4 POSTS
okay, let's start off with what i have done. i have replaced the following on my car listed above:

Radiator, radiator cap, cooling fans, water pump, heater core, engine temperature sensor, and relays.

After replacing/checking the above my cooling fans will now come on. but only when the A/C is running. They however still will not turn on when overheating. It will redline and the fans still will not turn on unless i run the A/C.
May 10, 2022 at 5:11 PM
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BORIS K
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 836 POSTS
Hello,

I would suggest to load test the wiring from the PCM to the 3 fan control relays.
See wiring diagram attached below,
If wiring is found to be in order would suggest to test/replace the 3 control relays next,

How to test wiring,
https://www.2carpros.com/articles/how-to-check-wiring

How to check relays,
https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Hope this helps,

Cheers, Boris
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May 11, 2022 at 5:51 AM
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