i have an 89 iroc 305 tpi and only the drivers side fan is turning on. today on the highway the car was running real close to 245 or so and i dont like that.
basicly my question is what do i look for to determine why the passenger side fan isnt turning on(besides a dead motor(but how should i test for that)).
hope this should be here and not in the electronics forum

 

If the passenger side fan isn't coming on, it could any of the following:
1) Bad fan motor - test it by running 12 volts directly to the fan
2) There is a fan switch between the #6 & #8 spark plugs. I believe it comes on at around 235+ degrees. Make sure the connector to it is in good shape. The switch may be bad. Becareful replacing it, it can get messy with the coolant.
3) The secondary fan should come on when you turn the A/C on and the A/C system has pressure (I forget what that amount is, but a working A/C system) and going less than 40 MPH. There is an A/C fan pressure switch on the high pressure line running along the passenger wheel well.
4) Relays - the secondary fan has its own relay. Check up by the firewall near the brake master cylinder. There should be 3 there, one for each fan and one for the fuel pump.
5) Blown fuse.
6) wiring.

These are the most common items that would cause the secondary fan not to come on and I'm sure I might have missed a few.

Hope this helps.

 

it does im going to look into it friday or saturday night.

 

i thought the right side fan was only for the A/C?

 

i think ill get a wiring diagram of it from school on moday than ill post it or something.

 

A quick and easy way to test the passenger side fan motor without applying 12 volts to it which you may accidentally ground out while trying to do so, is to take the wire coming off the fan switch itself and ground it. Then turn the ignition switch on (you do not have to start the engine just turn the key to on) and the fan should go on. This is how the fan switch works in the first place.

Good Luck Buddy!