20 circuit speedway wire harness

Discussion in '1947-1954' started by Guest5979, Oct 15, 2017.

  1. Guest5979

    Guest5979 Guest

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    Anybody using a 20 circuit speedway harness?
    straight six stomp starter nothing fancy need some help with ignition switch to fuse box hook up
    Thanks Robert
     
  2. Bill Hanlon

    Bill Hanlon Member

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    Kind of overkill for something that came from the factory with two fuses.
     
  3. coilover

    coilover Member

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    You are going to have a bunch of wires to be coiled up and taped off. The 12 circuit harness has several unused wires left over. I think you would be better off to return the 20 and get a 12. We did a 51 GMC with electric wipers, power remote locks, power windows, burglar alarm, huge sound system, back up lights, wiring for a 700R4 OD trans, 6 way power seats, cruise control, auxillary electric fans, power antenna---you get the idea. Still had unused wires with the 20 circuit unit.
     
  4. Guest5979

    Guest5979 Guest

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    Evan what brand 12 circuit harness to using?
     
  5. Guest5979

    Guest5979 Guest

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    I was told that the 12 circuit fuse box would not be able to handle a/c unit so I got the 20 circuit overkill
     
  6. coilover

    coilover Member

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    I use the Speedway 12 circuit for about $145. They used to be called "Mr Roadster" but I guess Speedway bought them. Dozens of ones we have done have a/c. If in doubt use a relay of any amperage you need. Just a few amps to activate relay which can then pass along big amps to the device. We always use a relay for cooling fan(s).
     
  7. Guest5979

    Guest5979 Guest

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    Stock ignition switch
    I hooked up the coil alternator starter wires to new harness able to start the truck but have to disconnect the battery to turn it off stock switch not cutting off the power should I get a universal switch ?
     
  8. Bill Hanlon

    Bill Hanlon Member

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    That won't fix it.

    My guess is you need a diode in the alternator idiot light circuit.
     
  9. Guest5979

    Guest5979 Guest

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    O boy more stress on top of stress so a diode connects to the alt than to harness?
     
  10. Bill Hanlon

    Bill Hanlon Member

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    Is your alternator new or newly rebuilt? A shorted diode in the alternator can cause this symptom.
     
  11. Guest5979

    Guest5979 Guest

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    As I think about it I think I put the coil wire to the starter wire making it a constant hot therefore no switch will be able to break the power feed sound about right? And if that's the case would a diode still be needed if I can get it turn on and off with switch
     
  12. Bill Hanlon

    Bill Hanlon Member

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    Coil power needs to be switched. Fix it and you should solve your problem.
     

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