Right Cletis. I hear you.
Since the alternator exciter wire is hooked after the switch, and the alternator power is before the switch, as well as the sense wire, I have to think that power (once in charge mode) is coming back through the exciter wire. But only when the sense wire is hooked up.
I have retrieved an old alternator that I had as a spare and I think I will hook that into the circuit and see if the behavior is differnt. I am thinking that once the alternator is energized, then it backs up power through the circuit.
Only the alternator exciter (which is switched, and the only part of the system after the switch) can be putting current back into the circuit and powering up the tail lights. The tail lights get power from the fuse box, through the light circuit. Power goes from the fuse box to the headlight switch to the tail lights, and from the fuse box to the brake light switch to the tail lights.
I guess what I should test next is hook the system up for charge, then see if hitting the brakes lights up more lights. I'll have to do with the garage partially closed, so it will have to be a quick test so I don't gas myself!
Blech.
I had a similar charging system problem on an old motorcycle such that when things weren't working right, the system would energize the lights. I suppose I could also see if the headlights are trying to come on and that might also tell me another part of the equation.
Power goes from fuse box directly to headlight switch (new) which then distributes power to the park lights and tail lights, and when all the way out, to the head lights.
