Speedometer round plug need jumpered to get power w/aftermarket gauges???

Discussion in 'Electrical and Ignition' started by Caco2120, Jun 13, 2018.

  1. Caco2120

    Caco2120 Well-Known Member

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    All,

    I purchased an aftermarket gauge cluster, and installed holley gauges, including a GPS speedo. In unplugging the factory cluster, I realized I have some power going through the headlight switch....and also appears the wiper switch. BUT the starter will only crank, and the headlights will only work, and the car will only run, if I jumper a wire from the battery direct to the coil. I assume this is back feeding power to the entire harness.

    My question is, since the headlight switch appears to jump power to parts of the harness, is there a spot on the round plug from the factory speedometer that needs jumped to get power to the rest of the harness??

    I have the "my mopar" diagram, but don't see this speedometer plug on it.
    thanks for the help!!
     
  2. Caco2120

    Caco2120 Well-Known Member

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    The plug that went here....do the poles need jumped together? imagejpeg_1.jpg
     
  3. 67Dart273

    67Dart273 Well-Known Member

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    No Nothing at the cluster connector

    What you need to jumper is the large ammeter wires, they are red and black, quite large, and the only two with eyelet terminals.
     
  4. Caco2120

    Caco2120 Well-Known Member

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    I found those and was using them as my power and ground for my holley gauges. I still dont have power to the lights or cranking power. With the dash unplugged...wonder what else um missing then.
     
  5. 67Dart273

    67Dart273 Well-Known Member

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    ??? The big black and big red ARE NOT A GROUND!!!

    The red end comes from the battery and the black end connects the battery end to several things, including feeding power to the headlight switch, ignition switch, etc.

    Here is a simplified diagram, this is the ammeter bypass article:

    Catalog

    amp-ga18.jpg

    Follow along......I am describing functional path, not electron flow

    From the battery, RED wiring, power ends up going into the interior of the car on the RED wire TO the AMMETER

    Right at the ammeter is where the black and red connected

    The black goes off and splits off at the WELDED SPLICE to headlights, ignition switch, and back out through the firewall to the ALTERNATOR
     
  6. Caco2120

    Caco2120 Well-Known Member

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    Oh my god thank you!!!....i would say i feel dumb...but a thick black wire i woumldnt initially think would be a POWER continuation.

    So i will jumper those two together with a small bolt...wrap in tape...and should have power to headlight switch, starter etc.

    Thanks again. Man i was stumped.
     
  7. 1994redram

    1994redram FABO Gold Member FABO Gold Member

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    How did you not melt everything when you hot wired the car to start?
     
  8. Caco2120

    Caco2120 Well-Known Member

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    Because i just ran a 12v to the coil. And that black continuance wire was hooked to nothing when i did it.
     
  9. TrailBeast

    TrailBeast Slightly Twisted Member

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    That black wire tricks a lot of people.:D

    It's also a REAL good idea to run a dedicated ground from the back of the cluster to the body.
    The wiper switch uses the cluster body for it's ground for the wiper motor counting on the cluster mounting screws to ground to the body, so without a dedicated ground it could end up finding a ground through just about anything connected to the cluster.
     
  10. 67Dart273

    67Dart273 Well-Known Member

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    LOL, we've all made dumb-ass mistakes. I would clog up this board if I could remember them all