ScottG - That was going to be my answer as well but surely he would have noticed some blown fuses if that was the case...
My reversed battery terminals blows one real close to the battery terminal and then two more labeled REVERSE POLARITY in the 12VDC Distribution Panel.
However my tongue jack is directly connected to the battery so I guess it might be turning backwards haha... Actually same goes for the slide in my fifth wheel. It too is connected directly to the battery terminals.
hmmm the kitchen items where the exhaust fan is located might be on the slide too ????
Would be easy to check to be sure - Find the word marked "NEG" or the symbol "-" on the battery case and hand trace this terminal cable to make sure it is the one that goes to frame ground...
Roy Ken