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Chevy Alternator Wiring Diagram

Discussion in 'The Hokey Ass Message Board' started by gahi, Apr 25, 2008.

  1. gahi
    Joined: Jun 29, 2005
    Posts: 731

    from Moab, UT

  2. jerry
    Joined: Mar 2, 2001
    Posts: 3,473


    That is the best I have seen. Very self expanitory.

  3. flathead4d
    Joined: Oct 24, 2005
    Posts: 889


    Excellent. I assume you could also just hook the #2 wire on the alternator directly to the battery post on the alternator? Yeah, I'm that stupid about wiring but had to ask. Thanks.
    Lester Piggott likes this.
  4. gahi
    Joined: Jun 29, 2005
    Posts: 731

    from Moab, UT

    ya, you can hook it direct.

  5. Bash'n'Weld
    Joined: Jan 19, 2008
    Posts: 361



    Got any more Chevy diagrams?
  6. wtf! no color?:D:D
    Joined: Jun 2, 2002
    Posts: 9,635

    Classified's Moderator

    YOu can also loop Bat and number two at the alternator...

    Then you only have the gauge wire (if you have one) and the line back to the battery to route.

    Get rid of the gauge wire and you're down to a homemade one wire alternator.
  8. Scott
    Joined: Dec 23, 2004
    Posts: 2,736


    You need the indicator lamp or a resistor to exite the alternator.
  9. zbuickman
    Joined: Dec 9, 2007
    Posts: 466


    you dont even need wire #2 the connected through a diode interaly. its just a sense wire if you use it:)
  10. 39ChevyRatRod
    Joined: Feb 6, 2008
    Posts: 57


    I didnt want to run a warning light on the excite wire and tried several way to hook it up, finally hit on a good way. Connect it to the unused pole on the starter that was originally used to supply power to the points during cranking, the momentary connection is all you need to get the altenator working then upon shutdown it cant backfeed the ignition circut. Works for me have done it several times. Just my 2 cents worth.
  11. 39 Chevy, That is an awesome idea. I'll have to try it. I love learning new sh-t!:D
  12. Mullda
    Joined: Apr 12, 2006
    Posts: 303


    Great post. THanks for the info!
  13. f-1freak
    Joined: Sep 15, 2007
    Posts: 88

    from Texas

    I was just trying to find out about this stuff. Thanks! :cool:
  14. Here's a one wire.-MIKE

  15. Thanks for both the diagrams, good job,,,,,,
  16. Great diagrams, guys. Everyone needs to see this thread, this question gets asked at least once a week.
  17. n95077
    Joined: Feb 16, 2005
    Posts: 13


    39ChevyRatRod, I tried your idea of using the resitor bypass on the soleniod on my bucket today and it seems to work rather well. Thank you
  18. Yaril
    Joined: Mar 13, 2006
    Posts: 989


    found this thread thru a search and rather than start another wiring thread ill just post my question here.

    i modified the above diagram (the second one). please let me know if its ok? *note that the ignition switch in my diagram is for a 50 Truck so it does not start the truck therefore i added a push-button start.

    other thing i would like to know is on the above diagram the alt and ignition switch have a wire that go to Batt. what exactly does that mean? excuse my lack of electrical knowledge.

    my modified version of the above diagram...


  19. LAROKE
    Joined: Sep 5, 2007
    Posts: 1,950


    Here's one that's similar to the first one but with external regulator. It's from Petersons "Basic Ignition and Electrical Systems", a Hot Rod Magazine Technical Library book published in 1971 which I bought back when I had pimples all over my face (well, more pimples anyway).

  20. michaell
    Joined: Jun 7, 2009
    Posts: 1

    from Arizona

    Best Idea I have heard since pop tops !!
    Thanks !!
  21. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,754


    I was just reading throuh my manual and read a few threads on converting a generator to altenator. So I drew up a diagram. I didnt include all wires on the back of the ign switch, just the ones relevent to the conversion. After I drew it up I saw this thread! So heres another diagram for the pile!! Let me know if its accurate!!

    Attached Files:

  22. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,059


    Thanks TM that one will get used tomorrow when I hook up the volt meter on my ot truck. Now to see if the wifi link to my wife's new printer works:D
  23. Dchaz
    Joined: Sep 6, 2009
    Posts: 481


  24. EZrider
    Joined: Jan 19, 2006
    Posts: 46

    from Waco, TX

    This diagram will let the alternator charge, HOWEVER, because the alt is capable of output @ idle, your vehicle will prob have RUN-ON problems; because the ignition can get fed by the alt thru the VM connections.
    TO eliminate this possibility you need an Ign sw w/ an ACC terminal.
    feed the alt off the ACC terminal, then when the Ign sw is OFF, the Alt & Ign circuits are isolated.

    I have fought this :mad:dog before & it still crops up.:eek:
    You shouldn't connect anything to the Ign term EXCEPT the coil pimary wire, ALL the gauges & other accessories need to be connected to the ACC terminal.
    For an old car, this usually means another, newer Ign sw.;)

    Old Bob
  25. cederholm
    Joined: May 6, 2006
    Posts: 1,621


    perfect timing! I just picked up a 1 wire GM alt for a 6v to 12v conversion on a '53 chevy. I'll review your diagrams before I begin - any do's don'ts or other thoughts before I start?

    Thanks! ~ and thanks for the great diagrams!!
  26. Thank you just what I was looking for.
  27. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,774

    V8 Bob

    gahi's diagram is the correct way to wire a GM 10SI/12SI, and utilize all the benefits of that great design. The output and sensor wire (#2) should go to the main power distribution location, as shown, not to the battery. The #2 wire ensures the 14.4 or so output is fed to the entire system, eliminating any voltage drop.
    Adding an idiot light or diode in line to wire #1 is no big deal, and can be placed under the dash instead of in it.

    Many make this wiring way more complex than it really is. Does a "one wire" work, and can you jump the #2 to the main output? Yes and yes, but the performance will NOT be as good as it COULD be.

    Open the link below, then "Electrical Tech", and learn all about the gen 2 GM alternators.
    Last edited: Oct 24, 2010
  28. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,180

    from Kansas

    Looks like a Ford diagram!
  29. d2_willys
    Joined: Sep 8, 2007
    Posts: 4,180

    from Kansas

    Voltmeter + can go to the ignition terminal, but the - terminal GOES TO GROUND. You have configured as a series element and that my friend will probably fry the voltmeter. In place of how your voltmeter is shown simply put a diode or idiot light.
  30. old lady's mad
    Joined: Mar 18, 2007
    Posts: 173

    old lady's mad

    the alt. will turn on anyway at about 1700 rpm. just hookup the batt. wire to the big stud and run the #2 wire to it .

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