Ok, the switch you are referring to is commonly called "salesman" switch. You will probably have another switch located in your battery compartment that will also turn off the house batteries. Check it first and make sure that it is "on". If still no power, check the voltages on your batteries....if fully charge, they will read about 12.6 to 12.8 volts. If discharged they will read only about 12.2 or less.
Let us know what voltages you find.
Ron
Ron & Sandie
2013 Tiffin Phaeton 42LH Cummins ISL 400hp
Toad: 2011 GMC Terrain SLT2
Tow Bar: Sterling AT
Toad Brakes: Unified by U.S. Gear
TPMS: Pressure Pro
Member of: GS, FMCA, Allegro
RETIRED!! How sweet it is....