'46 harness is pretty basic compared to modern wiring. I'd lay it all out on a bench and figure it all out with what you can see on your diagram, and service manual, compare with lengths etc. isolate the unknowns and chase down the ends with your meter. Once you study it out and have it labeled so that you have understand it, it won't feel nearly as overwhelming as it does when you drag it out of the box. Relabel with blue painters tape and a sharpie that you can tear off later if it helps you. (it always works for me) After you've got it all figured out, THEN install. And that will help with the "smoke test" that Jerry is referring to! There's just not that many circuits in a '46 when you are staying original. AND as always, it's great to be good, but a little LUCK never hurts, so good luck.
