If you have a bypass, it should be behind ( interior of trailer side of) the water heater. There should be 3 valves. You want the ones on the inlet and outlet pex to be in line with the pex tubing and the one between the inlet and outlet to be perpendicular to the pex. If you turned on the electric element to try the water heater without first insuring it was full of water ( operate pressure relief valve until water comes out) you may have burned up the electric element. Not hard or expensive to fix, but they only last seconds without water.
2015 Freedom Express 248RBS
TV 2015 Silverado HD2500 Duramax
TST Tire Monitors
Honda 2000I + Companion
2 65W solar panels