The series drive system was the first step away from resistor coils into the new controller-powered solid-state systems we know and love. It allowed for the inefficient bank of rings to get eliminated for a power-conserving controller-driven setup. One of the big players in this system is the E-Z-GO Forward and Reverse Switch Assembly. This unit is a copper-contacted switch that is wired directly to the motor. When you crank the knob, you flop the polarity, allowing the caddie to run in the opposite direction. There is nothing else on the buggy that has to change to make this happen. The solenoid and controller and everything else, for that matter, run the same way in forward or reverse.This is a copper-contacted golf cart switch assembly, so overtime, shifting, and heat will naturally wear it out. All you need to do is clean it up with some sandpaper from time to time, and when it gets too bad, call Buggies Unlimited and have us send out a replacement.