Guys- just got the fan relays fixed on an 87 GTA (dual fan setup). Everything works again except for the coolant switch in the passenger head turning on one of the fans.

My understanding is that temp switch, when grounded, should activate one of the fans. It doesn't.

Either I am misidentifying the wire or there is something else in the wiring between that switch and one of the fan relays.

Wiring info: There are 2 wires near the pass head temp switch that could possibly go to it. One white, the other black, both coming out of the same wiring loom (they are the only 2 wires coming out of that wiring loom). Black goes to the KS, white goes to the coolant temp switch. Can't go by the connectors because both are butchered, but I think that's correct. Grounding the white wire does NOT activate either fan.

Also, there are no white wires at either fan relay connector. It can't be a direct connection to either of them (as the tech article suggests). The activation wires at both of the fan relays is green with a white stripe.

What am I missing?

 

Just found this thread which suggests that I've got the wires misidentified:

https://www.thirdgen.org/forums/tpi/...me-thread.html

I'm going to try grounding the black wire and see if one of the fans activates. If so, I guess I have my KS and coolant temp switch wires plugged in the wrong sensors.

I would love to find out that's all that's wrong!

 

that's what it sounds like good luck

 

Yep, that's what it was- backwards wiring. 2nd fan works off the temp switch in the head now, like it should. And a functional knock sensor as a bonus. Amazing how everything works when it's plugged into the right places!!

A quick note- the wire color and the color of the plastic connector where they plug in are the same, which I guess GM did to give you a little hint. White wire and white plastic connector on the KS. Black wire and black plastic on the temp switch. Shoulda been obvious if I had thought about it a little longer.