Tail/brake wiring confusion.

Discussion in 'General IH Tech' started by mporter52, Aug 2, 2020.


  1. mporter52

    mporter52 Binder Driver

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    1973 Scout

    I'm using a "modern" universal harness.

    I'm wiring the rear lights and am confused. There are 2 wires coming out of the top socket of the rear brake/turn light. But I have 3 wires to connect.
    1. Brake
    2. Turn
    3. Tail light.

    If I connect the turn to the brake wire, both sides blink.
    If I connect the tail to the brake, wont the side marker lights come on when I brake?
    And isnt one wire one filament, and the other both filaments?

    How should I do this?

    Mike
     
  2. stevewillis

    stevewillis Farmall Cub

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    Ignore the brake wires in your harness. The Scout will switch the brake through the turn signal switch in the steering column. You should only need to connect the tail light wire to the dimmer filament and the correct side turn wire to the brighter filament in each bulb.
     
  3. mporter52

    mporter52 Binder Driver

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    Then where do the wires from your brake lights switch go?
     
  4. stevewillis

    stevewillis Farmall Cub

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    You should have a wire from your fuse panel through the brake pedal switch to the correct terminal on the turn signal switch in the steering column. That turn signal switch will handle turning on the brake/turn lights when you are braking and/or signalling a turn.

    For background, your generic harness is set up for a "modern" vehicle, where you have separate brake and turn signal bulbs. When you pull up behind a modern vehicle at a red light, notice that it can have a solid brake light on as well as a separate, flashing turn signal. The Scout is an older setup. If you pull up behind a Scout at a red light, the brake light itself will be flashing on and off if the driver is both braking and signalling a turn. There is no separate brake light.

    Which wiring kit are you using?
     
  5. stevewillis

    stevewillis Farmall Cub

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    P.S.: The turn signal switch in the column has a GM-style connector. You want to get voltage to terminal 'P' when you step on the brake (ask Google for some images of GM turn signal switches if you aren't sure which terminal is which). The original setup accomplished this with an always-hot wire from the fuse panel through the brake pedal switch to terminal 'P'. I don't know where the brake wires in your new harness originate, but you could run one of them to terminal 'P' and ignore the other to make your setup work.
     
  6. mporter52

    mporter52 Binder Driver

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    Thanks SO much for your help, its working now. I just now have an extra wire run all through my harness to the back. Haha.
     

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