Sometimes that switch gets left on "electric" by accident and the water is drained out of the TT. When you plug in the heater is dry (not enough water to cover the element) but the electric is "ON" and that ends the life of the heating element.
But with some luck you have a switch outside at the heater that is switched off.
No man has a good enough memory to be a successful liar. Abraham Lincoln
2016 36FBTS Pinnacle
2016 F350, 6.7, 4x4, DRW, long bed
B & W Companion 5th wheel Hitch