Anyone know the ins and outs of the factory dual battery setup e.g. do they isolate then start of one or two? I am told there is some sort of switch in cab factory for starting off 2nd ? or both?
What i am trying to figure is what i will need to keep from old truck e.g. Red Arc Isolator and deep cycle battery. On a major shed clean out so clearing all un needed shite and i am keen to know how it all works as no one seems to know

Any help appreciated