Does anyone know how the factory dual battery isolator was wired on a 79 Jimmy. When I got the truck it was not hooked up. There is one wire attached to the far right terminal (as you are facing the isolator) which I attempted to trace through the loom and it appears to go to some sort of relay on the driver side fender??? What does this relay or whatever it is on the fender do, there is not one on my 74 so i figured it might have something to do with the isolator. I would like to get it rigged back up but do not know where to and what to connect wires to. I used a marine type Perko switch when I did the dual yellow tops in my 74 which has a winch etc., but figured if there is already a factory setup in the Jimmy why not use it. Any advice much appreciated.