Electric Fan Wiring

Discussion in 'Sparky's corner' started by RetroAudio, Mar 9, 2023.

  1. RetroAudio

    RetroAudio Member

    Sorry in advance if this has been asked a million times. Google seems to be failing me.

    Is there a good spot to hook up electric fans to key-on power in my 72 skylark? Ran around the engine bay with a multimeter but I'd rather get advice from the pros before wiring it up.

    Any advice is much appreciated. Thanks!
     
    69GS430/TKX likes this.
  2. Bens99gtp

    Bens99gtp Well-Known Member

    I dont know what is done to your setup. But I would look to use a relay to run power to fan and not overload the circuits. Use an auto resetting circuit breaker in 30amp with a good 12 or 10g wire from the battery to pin 87. Run pin 30 to the fan power. Run pin 86 to ground and pin 85 to your 12 volt source you select.........if you wire the neg of the fan to ground it will run key on.....if you run the neg through a temp switch it will turn on at a set temp.....
    Its not hard at all
     
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  3. RetroAudio

    RetroAudio Member

    Thanks for the response! I have the relay all wired up, selecting the 12v source is my issue. Not sure what the best source is for running the relays to.

    Right now I have the the relays to ground waiting on a new 2-pin temp sensor to come in.

    Any advice on selecting a power source for 12v?
     
  4. TrunkMonkey

    TrunkMonkey Well-Known Member

    Anything that is powered with "key on" will work.

    You can run the trigger wire from a source (like the positive from the coil), radio, etc, from the fuse box. (tap on the "protected" side)

    I would recommend you add a 10 second delay, so the fans do not kick on when you go to start the car.

    You turn the key, 10 seconds later the fan comes on.
    10 seconds won't matter when the car is cold, and the car will start easier when warm with fans not coming on.

    The amps drawn on initial spin up is very high at the same time you are putting the heaviest draw with the starter (a hot engine with heat soaked starter).

    Search for Aharon Time Delay Relay 10 Seconds 5 pin 12V 30A
     
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  5. Bens99gtp

    Bens99gtp Well-Known Member

    Or turn key on wait a few seconds then start......or tie into a circuit that is key on but not powered on cranking and then it won't matter.

    The 30 amp for the micro second shouldn't hurt...........I have mine wired so the switch i added turns the ground on to the relays.......and i start my car all the time with the fan and water pump on......it never has starting issues
     
  6. 12lives

    12lives Control the controllable, let the rest go

    See if there is a loose yellow wire by the wiper motor. Some cars have them and they are keyed power.
     
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  7. RetroAudio

    RetroAudio Member

    Thanks for responses everyone. Time to dig around more tonight.
     

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