We have a bizarre problem! When I turn on a switch for a 12 volt light, sometimes it works. Other times instead of turning on the light it is turning on the vent fan which that switch does not control at all. Sometimes when I turn on a 12 volt light switch, all the 12 volt lights and the 12 volt vent fans go off as well as the refrigerator which beeps. This only started tonight and has never happened before. The camper worked fine at home. Now that we're at a campground and plugged into a 50 amp box, it started happening. We used the same box a year ago and it worked fine. Any suggestions as to why our 12 volt light switches are controlling things that are not even connected to them? And why that is causing the refrigerator to go off and on? Thanks so much for your help!