I second the need for a multi-meter. I had an issue with a 50 amp breaker near the battery location one time and after reset everything worked fine. I have had loose wirenuts which led me to just looking around and checking them where they tend to be in tight or hard to reach places. As a sidenote it isn't just electrical. I had a TV that one minute got a good signal from my satellite and 10 minutes later it was all snow, drove me silly. Last week while checking out my furnace, I found the cabling for the TV had rubbed on a sharp edge close to the furnace and TaDa, no more TV problems. It seems RV-ing means you are a part-time handyman also.