cooling fan only works with AC on

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Aug 7, 2001 | 04:26 PM

KNTA4DNU

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Joined: Jun 2001

Posts: 159

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From: Rochester NY USA

Car: '97 Z28

Engine: 5.7

Transmission: M6

cooling fan only works with AC on

Posting this for I guy I just met. He has a '92 RS 305. The cooling fans will only operate when the air conditioning is on. With AC off, no fan, car overheats. Thanks.

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87 Formula 305TPI T5

Aug 7, 2001 | 04:36 PM

Stuart Moss

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From: Warrenton, VA U.S.A.

If you have one fan: a bad Coolant Temperature Sensor (CTS) located by the thermostat with two wires may not be giving the ECM the proper temperature (resistance).

If you have two fan's, a bad coolant fan switch located between cylinders 6 & 8.

On a 92 V6 I had (one fan controlled by the ECM), I had a bad CTS. I could get the fan to operate when I removed the two-wire connector to the CTS with the engine running. Perhaps this "test" will work with the 305 too...

The CTS is the first thing I'd look at.

Aug 7, 2001 | 11:47 PM

Drkhrse89

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From: Shakopee, Mn

Car: 89 Iroc

Engine: 305TPI

Transmission: T5

I agree with Stuart on this one. It is the CTS the exact same thing happened to me about a month ago and when I put the new CTS in it was all good no problems.

Aug 8, 2001 | 11:03 AM

Kiss_My_SS

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Joined: Jul 2001

Posts: 42

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From: Lewisville, TX

I was having the same issue and replaced the CTS. The fan comes on but not until about 230. Is this normal? Also the heat never really gets real hot.

Thanks.

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Kiss_My_SS
1992 Camaro RS/Heritage Package
1996 Impala SS
1985 Good ol' Chevy 4x4 Truck