radiator fan isnt working unless a/c is on

**blackTA6585** · 09-30-2009, 02:08 PM

I have a 99 trans am and my radiator fan does not come on unless the a/c is on. My car wont over heat but it will run hotter when the a/c is off and when I turn the a/c on the fans come on and it starts cooling down some. Does anyone know why it would work when the a/c is on but not when its off? Do i need a new fan or is there a way to fix it maybe?

**BKHgto04** · 09-30-2009, 07:05 PM

Sounds like you need a cooling fan temperature switch. The fans are supposed to come on when you turn your AC on. This is good because it means your fans are working.

**sunsetorangess** · 10-01-2009, 01:07 PM

Are both fans coming on with the A/C on or just one?
J

**Cutlass** · 10-01-2009, 04:10 PM

From the factory, low speed cooling fans come on at 226*F and high speed cooling fans come on at 235*F. If you coolant temp isn't running that high then the fans won't come on (unless the AC is on).

**DaddySS** · 10-02-2009, 03:37 PM

the fans come on with the A?C irrespective of temperature. With a/c off, they are controlled by temperature sensor and the settingsin the PCM as stated above. if it's not overheating why wre you concerned - is it running hotter than usual?