Just to make sure, but you must be plugged into a form of 120 volt shore power for the electric side to work. The propane side will work off batteries but not the electric side.
Look on the backside of the water heater, for another main switch to turn on, and also to be sure the water heater is plugged into an outlet (which sometimes get's forgotten at the factory).
Also check your RV's breakers to make sure the water heater electrical circuit is flipped on.
Hope you find the problem.
2011 Flagstaff 831 RLBSS
I've just ordered a chicken and an egg from Amazon.... I will keep you posted.