I'm going to make a suggestion here that will definitely reduce the problem or at least help find one if one should occur. When you buy a rig, look at the the converter/distribution panel and using a DMM determine what each 120 volt breaker and each 12 volt fuse controls and write the information down and keep it with your manuals.
The original owner of our rig did this and he identified each wire and cable attached to the house batteries. I have used the list and it makes trouble shooting easier.
I have also done this for the breaker panels for every house or condo we have owned. It's a simple and easy thing to do.
"I travel not to go anywhere, but to go. I travel for travel's sake. The great affair is to go". R. L. Stevenson
David Bishop
2002 Winnebago Adventurer 32V
2009 GMC Canyon
Roadmaster 5000
BrakeBuddy Classic II