no power inside my 1994 Fleetwood Tioga class C

What voltage readings are you getting at your batteries? Are you getting the same readings at your battery soliniod? Are you getting the same readings at the 12 v fuse panel? The two things I would look at first if you are sure the polarity is correct is the cable connection to the inside of the terminals look for green corrosion or loose terminals. Also I found the set screws at the 12v fuse panel can sometimes loosen and need to be tighten.