1999 Vangaurd Cutaway Class C electrical issues

Yeah, I know my leads were not reveresed, I would hold them there and watch the voltage go from positive to negative just by switching from the converter to house batteries. The problem is, I do not know what wires are reversed, at the switch? I don't want to short something out and cause more damage. I can't even pull the switch out from the wall, there is zero slack in the wiring.

Thanks for the responce :)