The Stovebolt Site Forums The Shop Area The Electrical Bay Coil from 6v to 12v

I don't know what you're working on (always good to let folks know so they can give better advise), but generally speaking, a 12v system needs 12v at Start, and 8v (or so) to Run. When you turn your key (if you have one) to Start, 12v goes to the coil. When you let off your key (if you have one) and it goes to Run, 12v goes to the resistor, and from there to the coil.
Now wait for someone more knowledgeable than I am to correct me and good luck with your truck!