Question about 2004 Chevrolet Impala

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My radiator fans don't come on unless the AC is on what do you think would cause that?

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Most people think that the fans should be running all the time . This is not so. The fans turn on when the motor reaches a certain temperature this will cool the engine down then they will turn off then back on again as the motor heats up. M.ost vehicles will automatically actuate the fan motors when you turn on the a/c and keep them running while the a/c is on .This is normal. Try idling your vehicle for about thirty to fourty minutes and see if within that time your fans dont come on and turn of automatically without the a/c on.

Posted on Nov 29, 2009


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Posted on Jan 02, 2017

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SOURCE: radiator fan, ac, overheating problem. erradic

Get your A/c recharged .....

Posted on Jul 11, 2010

  • 83 Answers

SOURCE: radiator fans won't turn on

Radiator fans only need to run when the engine temperature exceeds a predetermined range for the sensor. I would think the AC bypasses the sensor via a separate circuit. The engine temperature would raise if for example the ambient temperature increases on a hot day or if you were clinmbing hills about the mountains, or if the radiator water level was low etc.

Hope this helps somewhat.

Posted on Sep 14, 2008

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SOURCE: radiator fan will not come

Have your cooling fan switch and cooling fan relay checked and replaced if necessary.

Posted on Oct 21, 2010

  • 188 Answers

SOURCE: when turning off engine ,

change the temp sensor on coolant system I am sure thets the cause.hope it helps

Posted on May 21, 2011

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1 Answer

Radiator fans won't turn on unless ac is running. why does it do that, how can i fix it?

Radiator fans only need to run when the engine temperature exceeds a predetermined range for the sensor. I would think the AC bypasses the sensor via a separate circuit. The engine temperature would raise if for example the ambient temperature increases on a hot day or if you were clinmbing hills about the mountains, or if the radiator water level was low etc.

Hope this helps somewhat.

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