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I'm about to install an electric fan on my '74 Vette and need help with the wiring. I ordered a Proform fan part number 67016 along with the wiring kit, Hayden part number 3651. My questions are: where do I get the ignition 12V source? There's a wire that says it should be connected to a constant 12V source, do I need to connect that? Won't it just keep the fans on all the time?
switched ignition can connect to the yellow wire on your windshield wiper motor and constant can go to the big post on your starter. you will hear other better ways , but those are the quick and get it running places. that system wont work without both connected.
Last edited by oldalaskaman; Jul 6, 2012 at 01:58 AM.
I ran a wire through the firewall to the fuse box for a switched power source and the constant 12v I pulled from the alternator with an inline fuse. I mounted the relays on the inner fender well (driver's side) just behind the hood prop so I could run the wire in the factory holders.
The relay is what prevents the fans from running constantly and your trigger will allow the fan to turn on or off. The trigger can be from a powered source such as the ac compressor kicking on or your relay be a - neg ground trigger from a temp switch either in the engine head or intake or a probe in the radiator.
The kit should come with instructions and you'll see it's really easy to hook up.
My 12v source was the back of the alt. for constant power and I found the ignition source from the fuse block. The ac I used with a thermostat controller so I had a lead to connect but if you're using a simple thermo switch, I'm not sure how to tie in???
I'll definitely run a 180* thermostat. I ran a 180* on my '78 Z28 and it ran great. That's a good idea on running the constant 12V source directly from the alternator. I'll do that for sure.