My 1992 Z-28 runs hot-just like everyone else's right? So I installed a toggle switch inside the cabin right next to the automatic window switches, which allows me to turn the fan on manually, but also allows the engine computer to turn it on also. My question: since the fan needs some much power, where should I draw power from? Fuse box, alternator, battery? Help??

 

another possibility is to interept the ECM ground for the fan solonoid, with a 3 position switch , wire one side to the ECM and the other to your own ground and the other is the wire coming from the solonoid under the hood. The current draw through this side of the solonoid is very low and any 16 gauge wire would handle it. Now I am not talking about the fans power wire (the thicker wire at the solonoid, if memory serves it is orange coming from the fuseable link and red/black going to the fan motor,) I am talking about the constant 12 volt wire that has its ground controled by the ECM.
Perry

 

So just by interupting the ground I could control the fan?! Huh. But then the fan would not be able to turn on when the ECM though it was appropriate, right? I'm worried that someday I might forget and burn the engine up. What do ya think?

 

I say just ground the fan switch and leave it running at all times. Thats what I did. Screw this intercepting crap. Run it all the time and forget about it.

Passenger side cyl. head, wire plugged in to it in the middle somewhere. Splice a wire on it and ground it to the car body/frame. Be done with it.

 

The previous owner of my Iroc did some serious messing with the wiring for the fans. Anyway I completely redid the wiring. I got a new relay and a jet fan switch. I Grounded both fans to the chassis, and ran 12 guage wire to the relay. And 12 guage to the fans. The trigger wire is 18 ga. and 12 ga. ground wire from the fan switch to the relay. The fans come on at 200 and off at 185. And it runs cool as a cucumber now. But it's still able to get up to operating temp. Unlike when both fans were running all the time.

------------------
Mario,
White 94 Z28
Yeah I got a few mods
Video
Black 87 IROC-Z

 

your not act. going to interupt the wire. your just goingto link onto it. find the ground wire that "control's" the fans from the ecm. all you do is add a wire to it and put it on a toggle sw. that goes to ground. then the pcm can still turn it on, but you can also turn it on like while at the drag strip.
thats what I did for my 95 and it works perfectly.
for my Iroc, I have LT1 fans in there and wired my own relay for each fan that are controled by one sw. on my dash. (full manual) a couple weeks ago I got almost all the way to work before I realized I didnt turn on the fans. lucky for me my cooling syst. works great, cuz it was "only" at 250 deg.. now i have a auto. kit from perma-cool that will turn them on at a certain temp, then back off when it reaches a lower temp. plus, I will have full man. control for the track.
chris