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Alternator Wiring

Discussion in 'Early CJ5 and CJ6 Tech' started by Don X, Mar 6, 2021.

  1. Mar 6, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

    San Diego,...
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    I'm rewiring my Jeep. Definitely out of my element.

    When I removed the existing wires I don't remember any leads coming of of the alternator with those being the jumper to the starter and power to the ignition.

    I have 2 terminals that don't appear to have used.

    Should there be a ground to the engine block from one of the terminals?

    Is the 2nd terminal for a tachometer which I don't have?

    [​IMG]

    [​IMG]
     
    Don X, Mar 6, 2021
    #1
  2. Mar 6, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    What style/maker of alternator? Better perspective will be helpful.
     
    timgr, Mar 6, 2021
    #2
  3. Mar 6, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Is that big lug touching the body of the alternator?
     
    Glenn, Mar 6, 2021
    #3
  4. Mar 6, 2021
    boopiejones

    boopiejones I can’t drive 55

    California east bay
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    I believe the two empty terminals should go to the voltage regulator.

    And I agree with Glenn that it looks like the lug is insulated from the body of the alternator at the terminal, but then touching the alternator body down by where the lug is crimped. I believe that wire feeds power to the battery, so you definitely don’t want it touching the body of the alternator.
     
    Last edited: Mar 6, 2021
    boopiejones, Mar 6, 2021
    #4
  5. Mar 6, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

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    The make of the alternator is unknown. The label on the side has seen too much dirt and grime.

    Thanks. This is why I keep you around.

    There's no exterior regulator. I assume it's internal.

    [​IMG]

    [​IMG]

    [​IMG]
     
    Don X, Mar 6, 2021
    #5
  6. Mar 6, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    You're welcome. And this further explains why we appreciate you posting pictures. :D
     
    Glenn, Mar 6, 2021
    #6
  7. Mar 6, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    I don't recognize it. Some features look GM, some look Ford. If it's one-wire, then there are no other wires to connect to it - just the big battery wire. Might be helpful to take a Q-tip to that label and see if you can make it more legible.

    Sometimes these have an added ground wire, but they also ground through the case. Certainly any ground lug will have continuity with the case.

    I've never heard of a tachometer driven by the alternator. You could have a connection for an ALT light, but then it's not a one-wire.
     
    Last edited: Mar 6, 2021
    timgr, Mar 6, 2021
    #7
  8. Mar 6, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

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    I tried Simple Green on a rag. No help. Guess I'll assume it grounds through the case and has an internal regulator. Any idea what the empty terminals are for?

    And Glenn, just for your peace of mind I went ahead and put shrink wrap insulation on the wire side of the lug.
     
    Don X, Mar 6, 2021
    #8
  9. Mar 6, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    First I'd check continuity. Possible they go nowhere. I'd take it apart and look. There are two brushes inside that connect the spinning part to the static part. There will be a way to hold the brushes back when you put it together. That's the only tricky part of putting them back together. Delco uses a toothpick, others have a removable brush assembly.
     
    Last edited: Mar 6, 2021
    timgr, Mar 6, 2021
    #9
  10. Mar 6, 2021
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    You did that just for me? :flag::beer:(y):clap::bow:
     
    Glenn, Mar 6, 2021
    #10
  11. Mar 6, 2021
    Don X

    Don X The Prodigal Moderator Staff Member 2023 Sponsor

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    Tim, I just wanted to figure out if I had to run a ground. It doesn't look like either of the empty posts have been used in forever. I'm just going to run the cable from the alternator to the starter like it was before. No need to fix something that isn't broken.
     
    Don X, Mar 6, 2021
    #11
  12. Mar 7, 2021
    SFaulken

    SFaulken Active Member

    Bellevue, WA
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    Diesels generally pull their tach signal from the alternator, because no ignition coil to read a signal from.
     
    SFaulken, Mar 7, 2021
    #12
  13. Mar 7, 2021
    48cj2a

    48cj2a http://bantamt3c.com

    Central Illinois
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    Some Delco Alt in Diesels pull the rpm signal from the Alt.
     
    48cj2a, Mar 7, 2021
    #13
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