Electric fan wiring help!!

Discussion in '94-95 5.0 - Specific' started by red9535, Jul 18, 2007.

  1. red9535

    red9535 Member

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    I got my electric fan, and i'm trying to decide how to wire it.

    If I were to just wire the ground to a ground, and the power to a 12v wire that gets power while key is on, and have it running all the time when the car is on, would that be alright?

    Any other suggestions? I'd like to avoid having it run to a switch, if possible. But, I'm considering running the electric fan, my fuel pump, and my ignition box, all to a switch inside the car. I could turn it into a killswitch, too. Get into the car, hit the switch.. fuel pump, MSD box and fan all come on, turn the car off and flip the switch and they all turn off, and my car won't start until it's flipped back on. I wouldn't even need to cut the ignition wire to make it a kill switch - the car won't start if the fuel pump isn't on :D

    Suggestions?
     
  2. ryclef331

    ryclef331 Well-Known Member

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    what year is your car???
     
  3. red9535

    red9535 Member

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    1995
     
  4. ryclef331

    ryclef331 Well-Known Member

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    whats with your stock fan?
     
  5. red9535

    red9535 Member

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    It is a stock fan, but I bought it as a project car. It was originaly a V6 that someone put a carbed V8 in.. so no sensor for me to use
     
  6. ryclef331

    ryclef331 Well-Known Member

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    ahh ok.

    You're going to need a relay to power it. There isn't a switch really that is going to handle the amperage that a fan is going to need. You need to pick up one of these to control it via temp.....

    http://www.streetrodstuff.com/Products/1042/

    OR

    you can get a standard Bosch Relay setup and wire it in yourself. I'd personally, fork up the 50-60 bucks for a controller setup and be done with it and KNOW its right.
     
  7. red9535

    red9535 Member

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    What if I just wired it to my 12v ignition and had it on all the time when the car is on?
     
  8. ryclef331

    ryclef331 Well-Known Member

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    You can do that but you'd have to run it so the ignition switches on a relay to activate the fan. You can't just tap into an existing circuit with a wire and call it a day. You'll fry the switch of the component you tap into AND / OR blow fuses left and right. A relay allows you to use a low current switch to activate something that is HIGH current. Your car has them under the hood from the factory for shit like fuel pumps, headlights, stereo, etc.

    What you can do is get a relay from the parts store....anyone will have them. Just where the relays are. A standard "bosch type" relay has 4 pins usually (some have 5...if you get one with 5, thats fine we just won't USE the 5th (center pin or "87a")).

    This isn't a diagram that I drew but it would look like this.

    [​IMG]

    your "remote turn on lead" is the switched ignition power that goes to pin 86. Pin 85 gets grounded to the chassis. pin 87 is your HIGH CURRENT 12volt supply for the fan. You should come right off the battery with this and it should be AT LEAST a 12gauge wire if not better. Pin 30 goes TO the fan....this will be the 12 volts that activates the fan. Now just ground the ground the negative on the fan itself!

    The way the relay works is when you put current ACROSS pins 86 to 85, that connects pins 30 to 87. Take AWAY current from 86 to 85, it will break the circuit from 30 to 87. Make sense? That would be the PROPER way to wire a fan in if you want it on all the time with the ignition on.
     
  9. red9535

    red9535 Member

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    So, this?

    [​IMG]

    Either that with the thermal switch, or jus run it through the relay
     
  10. ryclef331

    ryclef331 Well-Known Member

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    Yup....same thing. The diode on the fan and fusible link are additional safety items. The thermal switch is just a different way of turning it on.