That black with pink trace wire, in a original harness goes from the ignition switch to a ballast resistor, then to the pos. side of the coil then to the R side of the starter. It also goes to the back up lamp switch and lamps(if you have them), fuel tank sender and gas gauge, temp gauge and park alarm lamp. It also goes to the volt. reg., but it shouldnt turn into a brown wire. Hope this helps.