You should have a rocker switch that lights up red when you turn it on. It is usually located where the holding tank indicators and the thermostat for the AC/Heat controls are. That switch, when activated, provides 12v power to the water heater auto- start feature, and turns on the GAS to the WH burner. Once it reaches operating temp, the lighted switch will cycle off and on as required to stay hot. The switch on the outside panel under the cover should be OFF in this gas mode.
For AC 120v operation, the lighted rocker on the wall should be OFF, and the one under the outside panel ON. This powers the heater element- same as a home unit, for the water to get hot. What I do, and several oythers on here as well do, is leave that switch for AC power on all the time, but then you turn it off and on in the power converter panel box breaker. You'll see a breaker labeled water heater. Use this as your "switch" for the AC side. Just be SURE to remember to TURN IT OFF when you disconnect power to the camper. Hope this clears up your questions! And GOOD LUCK! Randy
/SIGPIC]'08 V-lite Flagstaff 30WRLS
'06 Ram 1500 QC hemi
Reese dual cam sway control,
K&N series 77 intake, Hellwig helper spgs. LT tires,
Flowmaster "true duals", 380 h.p., Bilstein shocks