ok...my sending unit has 3 wires coming out of it black/red and green/yellow. I traced the black/red to the fuse block. And at the tach the black/red and green/yellow appear again going into the 2 prong tach unit, however the unit has 2 wires coming out of it. Basically the only area that I'm totally confused about is what goes on between the fuseblock and the tack that allows unit to get power, or is it powered there? This black wire is new to me, but since it didn't appear at the tach or at the sender I don't know what to think. Thanks for the help though, I'll tinker around with it some more.
-Nate

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'82 240D, 4-speed, 617 turbo engine