electric fan wiring

[SELLERSRODSHOP]

what is the best method to wire up an electric cooling fan into the ORIGINAL 69 wiring harness? i'm used to having dedicated circuits on new wiring harnesses & not sure what the best method is for grafting into the original harness to power the relay & adjustable temp switch. i'll also be adding a 3G alternator to the mix pretty soon for the added amps to power everything up.

 

[johnpro]

I prefer the power signal wire be a switched source. I don't want my fan running, when the alternator isn't spinning. Been there, done that, had a dead battery in a parking lot twice before I wizened up. LOL

If you have the stock solenoid under the hood, still, you can just use the "I" post and the brown wire attached to it. Even if the resistor wire is still in-tact, 7-8v should be enough voltage and/or current to open the relay. Obviously, the relay should receive it's power directly from the battery, and needs to have a circuit breaker on it of ample size ... usually 30 amps will do fine. I use the self-resetting circuit breakers. They're available for a song at your local NAPA.

 

[66gt350]

When I wired in my electric fan, I did it similar to John with a relay and a resettable circuit breaker. But I used a ground wire as the signal to the relay, since that is what is coming out of the efi computer.