My single wire is also 3 wire....I got a new wire harness and it instructed me to put plug into alternator..didn't know what to do with the black wire...called the tech line, I just had to attach it to the rear post...it self excites....
(Sounds like someone I know.. Hmmmmmmm) anyway good luck

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1954 Chevy 3100 5-Window
In the Stovebolt Gallery
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"True victory is victory over one's self."
Krav Maga isn't pretty ... but it works just fine.


Jimmi V.