I should have added that I don't have any manuals that tell me anything. They are all component related, i.e. appliances, heater, sound system, etc. There is one large book that covers the, RV, but nothing concerning wiring other than the location of fuse panels (which have been checked). You're theory about what happened was exactly my thinking at the time it happened. Only problem is my lack of mechanical experience and no idea of where or how to start looking for the solution other than take it to a pro.