Fan Wiring
Thread Starter
7th Gear
Joined: Jun 2013
Posts: 7
Likes: 1
Fan Wiring
I have a 1978 that has had problems since I bought it; however, I believe I am now down to one issue. The car has an electric fan (after market and nowhere near stock) that is wired directly to the battery. The fan is pulling a great deal of amps when the car is in gear that is drains the battery faster than the alternator can charge it. (No drain on the battery when it idles in park.)
We are thinking that we need to wire the fan to the thermostat and/or engine somehow. Any ideas out there. Really appreciate your input.
We are thinking that we need to wire the fan to the thermostat and/or engine somehow. Any ideas out there. Really appreciate your input.
Race Director
Joined: May 2006
Posts: 18,703
Likes: 2,572
Drifting
Joined: Apr 2008
Posts: 1,305
Likes: 2
From: Lewisburg WV
thegazman
If you have the OEM 63amp alternator it's never going to handle an aftermarket fan set up no matter how you wire it. Get yourself a General Motors CS144, 140 amp alternator and it should solve your problem. Plus the CS144 charges a lot better at idle.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
what you need do is get an early a/c blower relay like on your car, with a pigtail, run a 30 amp fuse from one side of the contacts to the stud on the alternator output, NOT TO THE BATTERY CABLE.....then the other relay contact to the fans + fans - goes to frame/engine ground, obviously.....one side of the relay coil goes to a switched hot, such as the yellow wire on the wiper motor, other side of coil goes to whatever controller you want, computer, thermo switch, anything that will ground that end of the coil thereby closing the power contacts....
NOW if you have a/c you need put another relay in there to close/activate the fans when the a/c is on, regardless of engine temps....it be activated when the compressor clutch is energized.....
I have a FI setup on my car, so the computer takes care of fan operation....
