i have an 86 trans am , i dropped a built 355 tpi in there, with a aluminum 3 row rad, the ecm and wiring is from a 87 iroc, i deleted the a/c, even the heater, only gonna drive in summer when weather is good. now my question,, i dont have dual fans in the car i have the stock 86 single fan, since i dont have a/c , and i deleted half the harness to have only one relay to my fan,,,, now what should i use to trigger that single fan? i have, 1. the stock temp switch on pass head,2.a temp switch on my new rad 3. the ecm that takes the info from that temp switch on the intake below throttle body, can i use the gre/wh wire from the ecm and both switches on the same relay?? should i rely only on ecm? only on 1 switch? 2 switches? if i use the ecm at all,,,, since i have an 87 wiring, do i ground, or open the blue wire from the a/c? cause i dont have a/c ,,,the car i took the ecm and wire from used to have a/c. if i dont use the ecm,, can i just leave it like that or is there something i should change not to mess up anything,,,,,, i just dont wanna try a bunch of things, want to wire the car properly once,, and hide harness with loom once and for all,thanks.sorry for the looooong question

 

You just need to throw a ground on the relay. So its pretty much your choice. Which one has the correct temp on?

Personally, I would use the head switch positon. Stock one I had was like 220deg, So I got one from napa that was 190deg. There wouldnt be any problem wiring them all together, if one failed you have a backup.

I have the head postion switch/ecm & my driving light switch wired up to turn on fans.

The switch on your radiator, its on the hot side?