I did a search to avoid making a thread, but my results were unfruitful. I tried wiring my own switch and ended up blowing a couple of fuses and replacing the alternator.... I have an 87 Trans Am (LB9) with dual electric fans. Like most of you, on bad stop-and-go traffic, it tends to over heat. I would like to wire 2 switches to turn on each fan. I have included a picture of the 2 relays for the fans. Relay#1 (which I believe is controlled by the ecm). It has 5 Wires; thick orange, green/white line (1), 2 tan/white line (2 and 3), and thick black/red line (4). And Relay#2 has 4 wires; thick orange (3), green/white line (1), tan/white line (2), and thick black/ red line (4). At the moment, everything is stock, I know a few wires are spliced, but they have loosed, protected ends. I need to know what I need to do to wire a switch if possible... do I need to ground wire 2 and provide 12v (15amp, 20amp, 30amp???? with switch) to wire 1? Or is it the other way around? I know the thick wires provide the power to the fan, so I'm not messing with those. I just need to know what wire needs to be wired to what and whats supposed to be grounded and such. Thanks.

 

I don't have a diagram, but,
If you know what is supposed to be the hot wire for the fan, "each one"
Run a wire off the bat, to a relay, then to the fan. Ground the second fan wire.
For the switch I would run a wire from something off the ignition, to the switch, to the relay. Then ground your last wire. I would do this so you cannot leave the fans on and kill the battery.
Or if you don't care about that you could run your switch wire from the battery terminal on the relay, to the switch, back to the switch terminal on the relay, and ground your last terminal.

Having said all of this, the best way to wire all of this is to leave it set up stock, or get an aftermarket wiring kit.
I say this because it is not good for the fans to run constant. If you fix the factory setup, you can get a differnent temp switch to turn them on sooner.
But a temp switch is the best way to hook up an electric fan so it dose not run constantly, and burn up.