Wiring hook up for a/c to control electric fan

  • #1

    Wiring hook up for a/c to control electric fan

    I'd read the threads and went through the search. I'm just coming across a few questions about hooking up the e-fan to the a/c system. I know I can hook it up to the compressor but I'm not sure if I like the idea of it cycling on and off with the compressor. Is there a separate wire I can use to hook it up so that it will turn on when the a/c system is on and not just the compressor? Also, I've heard of different people hooking up a dual speed fan to come on high as well as low. Which speed would be better? Is there any problems with being on low w/ the a/c or does it need to be on high (I have a taurus fan).
  • #2
    People who use the ac to control an electric fan don't have the ac to worry about. Thats kind of the point.
  • #3
    My a/c is functionable. I'm going to use a relay to power on my fan when the a/c is engaged.
  • #4
    So you want to use the AC button as a switch for the fan? Or do you want to run the fan while you run the AC?
  • #5
    I want the e-fan to switch on when the a/c is running. I need to find a wire that the ground or power feed leads to when the a/c is on.
  • #6
    I think you can use one of the wires that go to the relay box behind the passenger side headlight.
    Shiro #443

  • #7
    You can also tap into the wire going to the ac compressor. It only gets powered if your ac is on but the defrost will cycle it if you use defrost. This is what I did and it works great.
    '85 300zx turbo: exhaust, intercooler, coilovers, etc…SOLD, will be missed
    '86 300zx turbo: starting over
    '97 Dodge 2500: 12v Cummins …selling and will be missed
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  • #8
    So if I wire it directly into the compressor feed line; it will remain on the entire time the a/c is on and only cycle on-off if the defrost in engauged?
  • #9
    perna00 wrote: So if I wire it directly into the compressor feed line; it will remain on the entire time the a/c is on and only cycle on-off if the defrost in engauged?
    corrrect, i never really drive my car in the winter so i dont use defrost.
    '85 300zx turbo: exhaust, intercooler, coilovers, etc…SOLD, will be missed
    '86 300zx turbo: starting over
    '97 Dodge 2500: 12v Cummins …selling and will be missed
    '94 Jeep Cherokee: D60 Front 14b rear, both locked and 5.38 gears, 37" mtr's
    2015 Ram 2500 megacab laramie cummins black appearance package
  • #10
    Thanks for the info for the wiring. Does yours run on high or low when you have the a/c on?
  • #11
    Personally I have a 2 speed taurus fan and I run low all the time and I have high come on if it hits a certain temerature set by me or if the ac is turned on.
    '85 300zx turbo: exhaust, intercooler, coilovers, etc…SOLD, will be missed
    '86 300zx turbo: starting over
    '97 Dodge 2500: 12v Cummins …selling and will be missed
    '94 Jeep Cherokee: D60 Front 14b rear, both locked and 5.38 gears, 37" mtr's
    2015 Ram 2500 megacab laramie cummins black appearance package