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Thread: New member with 56 CJ-3B

  1. #11
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    Thanks for the links! It is a 12 volt system. Now that I’ve got the system charging it puts out just under 14 volts at a high idle. I’ve posted a pic of what I was referring to as a voltage regulator or reducer. I measured the voltage at each end of it when I got the lower voltage.
    D6F3F398-6878-43BF-8223-F1D8C624ED05.jpg

  2. #12
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    Sorry for the sideways pic. I’m doing this from an IPhone. For some reason it’s turning them. Also, when I open a post and click on a pic it messes up on my screen. Maybe I need to be on a computer?

  3. #13
    Super Moderator LarrBeard's Avatar
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    Basic 12-volt conversion

    Quote Originally Posted by Mchambers View Post
    Thanks for the links! It is a 12 volt system. Now that I’ve got the system charging it puts out just under 14 volts at a high idle. I’ve posted a pic of what I was referring to as a voltage regulator or reducer. I measured the voltage at each end of it when I got the lower voltage.
    D6F3F398-6878-43BF-8223-F1D8C624ED05.jpg
    You seem to have a basic 12-volt conversion.

    I'd bet the original generator was swapped for an alternator with an internal regulator, so you don't need the original three-terminal voltage regulator.

    Headlights and lamps were changed to 12-volts, but changing out the sensors and gauges was a big task, so the voltage reducer is just a series resistor that drops the 13.8 or so volts of the system down to about 6-volts. (13.8 is just about right for a charge voltage).

    It's not elegant, but it works.

    You look good to go.

  4. #14
    Super Moderator LarrBeard's Avatar
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    We can handle sideways and upside down. If you're up under the dash, it's upside down anyway.

  5. #15
    Super Moderator bmorgil's Avatar
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    I did not see the use of the Ballast resistor on the other side of the air cleaner with all the wires hooked to it.

    Larry, are you saying they are jumping off the ignition ballast resistor to drop the voltage? That would be a tough way to "drop" the 12 down to 6! How would you know how much resistance to use? The ballast resistor drops the coil voltage to about 9 volts depending on the current draw of the coil. If that's what was done your idea in the other post about the Solid State voltage reducer is a MUCH better way to go.

    Take some pictures of the back of the alternator Mchambers, lets see if that is a "One Wire" or an internal regulator as Larry suspects.
    Last edited by bmorgil; 01-04-2021 at 08:12 AM.

  6. #16
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    E66C6D28-09CA-4099-B35E-2CBDFE1218F9.jpgBmorgil, I’m attaching some pics that hopefully will answer your questions. My alternator has only one wire coming from the two spade connector. The other picture is a better view of the part I’m thinking is a reducer.
    Thanks,
    Mark
    A552C30F-081C-4BC0-9203-9203C8DB5A40.jpgA552C30F-081C-4BC0-9203-9203C8DB5A40.jpg

  7. #17
    Super Moderator bmorgil's Avatar
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    The white "reducer" is the ballast resistor. It looks to me like it has 3 wires on it. One wire should be coming from the ignition switch on one side of the resistor. On the other side of the resistor one wire should be coming from the starter or starter solenoid and the other wire hooked to the positive terminal on the coil. The coil uses 12 volts to start and 9 volts to run. It is not part of the charging circuit unless it is hooked up as Larry suspects.

    I think you have a GM 10si alternator in there. I am not sure how it is hooked up but, here is a quick look at how it SHOULD be hooked up! As Larry said, trying to figure out how it was converted without being there is tough. Lots of pictures. Can you get a picture of the backside of the alternator? That will help verify exactly what it is. It looks like a "3 wire". One large wire on a post to the battery + terminal or starter solenoid and two smaller wires in a spade plug that operate the charge light or gauge and the excitation of the field.
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    Last edited by bmorgil; 01-04-2021 at 08:13 AM.

  8. #18
    Super Moderator LarrBeard's Avatar
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    12-volt Troubleshooting

    WE may have Girarffelephant here - or a Hippogator. The Hippogator is a mythical beast with a head on both ends. That makes him really mean ...

    I need to scratch my head a bit ...

    Does the CJ 5 have an ammeter or just a charge light? I don't have that Shop Manual.

    It ran OK once upon a time, now it doesn't, so let's not go crazy fixing things that don't really need to be fixed. I'd say battery and alternator for first steps.

  9. #19
    Super Moderator bmorgil's Avatar
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    Yes I agree. I think step one is some verification. Set the Mutlmeter to Volts and the range to 20 or whatever you have near that. With the engine off measure the voltage across the battery terminals. Start it up and measure the battery voltage across the terminals again. Rev it to a very fast idle and measure the voltage across the battery posts once more with it revving. Gives us a shout with the results. Lets start at square one.

    The CJ5 had an amp gauge. The "field" on a 10si Alternator used a charge light in the field circuit. The 10si can be made to charge in various ways with or without a charge light. We can figure that out later if needed.

    You stated you did get 14 volts at high idle. Lets verify that and see what you are getting from the battery when it is off and from the battery when it is idling. If it is going dead with good voltage readings, there is a current leak somewhere or the battery is sulfated.
    Last edited by bmorgil; 01-05-2021 at 07:42 AM.

  10. #20
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    Guys, think we have 2 threads mixed up!!Lol. My alternator has a threaded stud with a wire going to amp gauge on dashboard and then a 2 blade connector-which uses only one of the two blades- and that ONE wire goes to the ignition terminal on my key switch. It is a Delco 42 amp alternator.
    BAB8BB81-18BB-427F-902D-53682D7D2C34.jpg

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