Well, the good thing about the factory wiring schematic is that it calls out the colors of the wires with tracers and all of the components in clearly written form! It's pretty easy to trace where a wire goes simply by following the color of the wire! I'm not trying to be a know it all, I'm just stating what Del said over and over, which rings true! If you're going to own a car for any length of time, compile a stockload of information on it, and the factory service manual, and wiring schmematic in this case is the definitive answer! Just as your suggestion alludes to, get information, study said information, and head into the project with said information!