Help with rear light harness

[crashmod]

That may explain why at one point the volt gauge was only showing 10 volts at times but would jump back up to around 13.5-14 volts once the motor went over 2000 rpm's. The motor is out of a 92 model truck but I can't remember exactly what alternator I used. I believe it is a 1-wire but I went ahead and hooked it to the original factory wiring instead of using just a 1 wire hookup. I'm slowly going through the wiring on the truck trying to chase down all of the wiring issues that it has. Almost to the point of just buying a new wiring harness and starting over.