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One vs three wire alternator

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  • One vs three wire alternator

    I have a 81 natique with a Ford Windsor. I recently went through and redid the starter, voltage reg, and new battery. Had the alternator tested and it was putting out charge. This summer my alternator a three wire prestilite was putting out no voltage. I'm suspicious I wired it wrong for it to coincidentally fault right after I redid everything.Looking online a lot of people are moving to one wire systems. What is the advantage to this system? The alternator is actually cheaper as a one wire which makes me suspicious. Has anyone else rewired one of these? Any favorite brands?

    This is my first rebuild, any help would be appreciated

  • #2
    this diagram may help you check to see if you wired wrong. I am not expert on such things, but went from three wire to one wire many years ago. Not because of price or preference or advantage, but because it was all I could find close by and I wanted to get back on the water. Its not really a "rewire", just hook up one of the three to the new alternator. Unfortunately, I cant tell you which of the three, but I am guessing its the orange.

    I dont know how many are out there, but I pretty much think Delco is the go-to brand, and comes in different amp outputs. Click image for larger version

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    • #3
      Did your old alt have a external voltage regulator? Think the one wire jobs have internal one. New to the boat thing but the old ford cars that had generators we would change them over to GM Delcos with one wire and by pass the external one. Maybe will help


      • #4
        I'm not expert but the original set up had an external regulator. I never did anything with it and assumed it was still functioning, but you are right, based on this little bit of research the 1-wire has internal. Maybe I bypassed the VR without knowing it by leaving off the two other wires that went to the original. Wires all pass through a harness, so never traced. Click image for larger version

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