I enjoy working on my XR650R but don't get the electrical stuff. So I'm looking at my rear brake light wires - because I'm going to connect a Baja Designs front brake switch - Brown and white wires go in to their connectors but a third green/white wire with connector is not plugged into anything. Is this a ground? I don't see where it goes. Anyway, how can I really get this electrical stuff down? The shop manual doesn't have much detail other than a general schematic. Do I have to get an electrical engineering degree to be able to wire one of these bikes? Sheeesh!