Since my Mercathode had voltage going to it regardless of the battery position on the GUEST Switch, then I believe I am "hard wired" to one of the batteries somehow thru the wiring harness in the panel. But what is a bit baffling to me are the various voltage readings I get when moving the switch around to the various positions. If the mercathode was connected directly to the battery terminals, I wouldn't have seen any voltage flucuation since the switch would have been removed from the equation. So why did I get the various voltage readings and would it be possible that asimpkinsjr is wired incorrectly into the wiring harness? Unfortunatly (for me) you guys are a bit more informed on electrical things than I am but would it be possible to come up with a simpler explanation here that might explain my situation as well asasimpkinsjr situation? Or maybe you have done that and I am just not smart enough to understand. :smt017