I want to use either a fog light or rear defroster switch to make a “Fan On/Off” switch, and also be able to keep the sensor running (For winter months and emissions testing).
I have an idea that I could just a splice into the fan switch wire, then put that onto the fog light switch, but not sure where to get the power source from for the light that is in the switch.
Could I just use the wires from the relay? Anybody know what wires I would need to use? Any help you could give would be greatly appreciated, before I go out and just use trial and error

 

I just helped a friend get his fan working in his 87 IROC. Does your car have single or dual fans stock? If dual, you'll want to use the wires to the primary fan relay. If single fan stock, well then you'll only have one relay.

Regaurdless, to do this properly you'll have to use the relay. What you can do is run a wire from a ground to your switch. From the switch, run a wire that splices into the wire from the ECM to the relay. On my friend's 87 it may have been a green and white wire but dont quote me on that. It will be one of the thinner wires going to the relay. If you simply tie into this wire without cutting it, your fan should also come on from the ECM control.

Good diagrams, Trickster!

 

Hello Jconrad,

Here are a couple of diagrams another member posted on here recently.

 

part 2

 

Thanks for the help, guys. I also just got a response from Willie with his wiring diagrams for the Total Fan Control. It includes the instructions on how to make a Manual On switch too
Trickster, I copied those diagrams for future reference, too
Now I just have to find me a good fog light switch to make into my Fan On/Off switch, with light that tells me when the fan is actually on. Turn it Off, and factory settings, and on when I need the extra cooling. I figure this will be better than just keeping the fan on the whole time the engine is running.
After I get it all done, I'll post here to let you all know how it turned out.
Thanks again