Make sure that you have the bypass valves in the proper position. There are numerous threads on this forum concerning that.
The bypass valves will be found on the inside of your camper near the water heater....you may have to pull a cabinet panel or something depending on where your water heater is located.
For proper valve position, check out post #2 here: Winterization Confusion
The switch on the inside of the camper controls the gas side of the water heater, and the switch on the outside part of water heater controls the electric side of the water heater.....along with the appropriate breaker in your power center. Both do not need to be on at the same time, as they are entirely 2 different systems.....but they can both be on at the same time if you want slightly faster water recovery.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263