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Thread: wiring of alternator

  1. #1
    Freshman Member
    Join Date
    Oct 2016
    Niskayuna, NY

    wiring of alternator

    I am in the process of changing my BJ8 from positive to negative ground. I have changed the fuel pump (electronic) and the points (Pertronix) and installed the new alternator. I will attack the Tach issue later. So my question is on the wiring of the alternator. I have the diagram that came with the kit from Moss. I have looked at the video that Moss has on its website. I am still confused. I have 2 wires coming from the alternator... the "D" wire which is a large wire and the "F" wire which is a small wire. I have traced them and they both go directly to the voltage regulator and are attached to the tabs marked "D" and "F". On the voltage regulator I have the following tabs "E" (for earth or ground), "D" (for Dynamo), WL (for warning light?), "F" (for field) and 2 tabs marked "B" (don't have a clue what the B stands for) with 3 heavy brown wires going to them. From what I have read and have seen on the video I am pretty sure that the "D" wire needs to be tied to the 3 "B" wires. I assume that the "F" wire and the "WL" wire need to be tired together. And then I am done. Is that correct? Am I missing something? As always any help is greatly appreciated.

    '65 BJ8

  2. #2

    Re: wiring of alternator

    Is this the Lucas alternator? Does it have an internal regulator? If so you're only using the old reg as a junction strip for the various wires. The reg is usually either gutted or all the fusable links on the bottom are cut. I ran a separate 10 GA wire from the alt to the cable connection on the solenoid.

    If you use the stock 12 GA yellow wire to carry the current output, it joins to the 3 brown wires. The small yellow and yellow/green wires join - they're for the idiot light.
    The wire for the field terminal comes from the ignition switch.

    Suggest you add a voltmeter. The dash light doesn't do much of anything.

    This is how I did it:
    Steve Gerow
    Altadena, CA, USA
    Maker of most complete Big Healey rear disc kit
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  3. #3

    Re: wiring of alternator

    Here is a diagram of the circuit I built into my BJ7. The "Main Bus" in the wiring diagram is the location of where the voltage regulator used to be. You can either remove the regulator and use a terminal strip as I did or you can cut all the connections to the regulator terminals on the back of the regulator. I figured why ruin a good regulator and I wasn't trying to fool anyone with my alterations. Simple is best to me. So I used the terminal strip.
    A couple exceptions to the wiring diagram is that (1) don't bother to put in an amp meter. It won't record properly as I have it anyway. Just run the #10 red wire from the alternator "B" terminal to the "Battery" terminal on the starter solenoid. That gives you a much heavier wire for the charging current from the alternator to the battery.
    Exception (2) is that I believe I mislabled the wire on the alternator marked 'R' or on some alternators it is marked '1". On my drawing it shows as yellow/brown I pretty sure it is really a yellow/green wire. Steveg above mentioned it as yellow/green and I go with that. (i really should change my drawing). As you can see at the regulator location where i use a terminal bar (main bus) this yellow/green wire is attached to the small yellow wire which goes to the ignition charge indicator light.
    I have also attached two pics of my engine bay for you to see what the connections at the voltage regulator location look like in real life. I believe the pic a clear enough that you can pick out the wire colours there also. this wiring has been working in my BJ7 for 4 years now.
    Attached Images Attached Images
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  4. #4
    Darth Vader John Turney's Avatar
    Join Date
    May 2002
    Concord, CA

    Re: wiring of alternator

    Much depends on which alternator you have. If you have one like shown in this Moss Motors video:, the two wires can be attached as Moss described. The fat wire goes to the "D" regulator terminal and jumpers are added between the "D" terminal and terminals "A" and "A1". The thin wire is tied to the warning light. All the other terminal are unused.

    I have a GM 10SI alternator (used in the late 1970s to 1980s GM cars and trucks). It has three wires and is somewhat differently.
    John, BN4

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