There is nothing special about that wire. It brings in 12v from the light...
It connects to a contact that seems to missing in your vid (among other...
Yes the alternator regulates the voltage internally in the alternator. There is an external connection to remotely sense where the voltage reference...
When I was running the original type pump, I put a temp sensor if the feed line at the tank and the return line at the tank. My pump would buzz when...