Originally Posted by Phil_J
On our TT just plugging in the trailer doesn't turn on the water heater. There is a switch at the water heater that has to be turned on as well.
If that switch isn't turned on you should be okay. But yes there needs to be water in the water heater before turning on the power switch.
X2. If you have a Suburban heater there is a switch outside on the heater itself as well as a switch somewhere inside, usually with a red light next to it and there is probably a breaker in the power center for it also.
If it's an Atwood heater, there is no outside switch but, the other 2 inside should be the same.