One the hitch there is wiring coming from the battery to some kind of a connection. The reason I am vague is because it is right next to the battery box so hard to see the entire thing. Anyway, when the camper is unplugged, there is the correct voltage from the battery but nothing on the other side. When the camper is plugged in, there is voltage on both sides. Next weekend my husband will be unhooking the batteries and removing the boxes to get to that connection. Not sure exactly what is in there yet - if there is a fuse or not because you just can't see it with the box in the way.