Originally Posted by Tantanthefishman
I did that overnight and water still hasn’t warmed... any clue?
If you have an outside switch, it's a Suburban. This outside switch only controls the 120 volt electric heating element, and you must be plugged into a form of 120 volt AC shore power/generator for it to operate in that mode. I recommend reading this thread first, as it explains how to make sure you have water in the tank, and do not burn out the heating element.
If you are connected to shore power and have verified you do indeed have 120 volt AC power to the RV (is the microwave lights/display on), then make sure the circuit breaker in the RV's electrical distribution panel is on (not tripped) to the water heater. Here is an example pic, but styles vary:
We have many instances of the water heater itself not being plugged in to an outlet. You may need to access behind the tank and see if you can see a power cord and that it's plugged into an outlet (some are direct wired, and some just have a plug in cord). Here is a pic of a members whose power cord was just laying on top of the tank and NOT plugged into an outlet:
Also on the face of the water heater there are two reset hi-limit thermostats underneath a rubber cover. You can push in on the rubber cover to make sure these have not tripped. The left one goes to the 120 volt electric element.