Don't know about the inverter and I'm not into motor homes. But, these are the three places I've seen the patio light switch in trailers. 1) On the light itself. 2) On the wall near the door. 3) On the bottom side of a cabinet next to the door or under the protruding lip of a similarly located counter. These last can be quite out of sight. One further long shot, some units had a semi-recessed grab handle for the entry door. Often there was a light in the recess. If you have such a setup, take a look in there.
Happy Camping! ///// Richard D.
2006 4x4 Ford 250 SD / 2007 Flagstaff 827 FLS
One very patient wife and one furry child who travels with us. Forty-two years of trailering and camping, and I still have a blast.