I have the dual electric fan set-up on my IROC. The car is over-heating with the gauge going way past 220 when I am stuck in traffic, but runs nice and cool when I am on the highway. I tried to figure this out myself but ... When the car heats up, the driver's side fan runs but the second fan (pass side) never comes on no matter how hot it gets. I exchanged the fan wires and the pass. fan came on - so I know the fan is good. Are there seperate relays for each fan? Are both fans supposed to kick on at the same time? Where are the relays? Sensors? What am I looking for and what should I do? Thanks in advance.

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Black 89 IROC 350 TPI

 

I have the same problem on my 1992 Z.It can be several different things such as the coolant temperature sensor or the ECM. Good luck!

 

The ECM doesnt control that fan. Does running the AC turn on your second fan? Check it out and let us know. Also, the fan switch that activates it is located in the passenger head, between the #6 and #8 plugs. When the coolant gets hot enough, it is supposed to ground the wire going to this sensor, and therefore turn on the fan. It is not too expensive, and if your sensor is pretty old, it might be cost-effective to just simply replace it.

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1989 IROC-Z 5.7L
NOS 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

[This message has been edited by Omar (edited July 12, 2001).]

 

It looks like the second fan comes on when I run the AC, therefore keeping the temp down. So ... when I am in heavy traffic I need to turn on the AC? Is the second fan only for the AC? Shouldn't both fans turn on when the car heats up?

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Black 89 IROC 350 TPI

 

You may want to consider using an adjustible temperature fan control switch from Pep Boys to control the secondary fan. It may be connected to the same wire going to the sensor in the passenger side cylinder head to control the fan.

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Tim

1992 Z28, 305 TPI 5 speed, 12.1 sec @ 114.7 mph

1984 Berlinetta 305 TPI Auto, 13.8 sec @ 99.7 mph

 

I had a similar problem last summer, where the pass fan wouldn't come on. The drivers would come on with the A/C. Went to a junkyard, and clipped an already bad harness. One wire to ground, and another to the ignition. Now the fan turns on when the car is running. Runs fine now. Couldn't figure out why it wouldn't do it automatically. Replaced all the sensors and gave up. Could wait in Texas heat in August!