I have yet to figure out what that Keystone supplied switch does. I turned it off - the lights still worked and the slides still went in and out. On our last, everything but the CO detector shut off. I have a total system switch to install one of these days.
Now, that total system switch and which side to use - in my car race days it, by organization rules, had to be on the + side and the side I normally use. But with that said, virtually everything RV I've read says the - terminal. To use the + side, you are taking all potential out of the system while using the - side, the potential is still there, waiting a screwdriver or whatever to reestablish the full electrical path. But doing it through the + side, maybe not quite so simple. Conundrum since the same argument can be said for each way
