rbpru wrote:
Well I will put it this way, when I am not on shore power and turn on the water heater switch it lights up.
Of course it does, you have a DSI (Direct Spark Ignition) water heater that's running on propane gas and requires 12 vdc to operate the DSI function. Some models do have an optional 120 vac electric heating element but obviously it's not functional unless your trailer is plugged into shore power or other source of 120 vac power such as a genset. There are none that I know of that have a 12 vdc heating element as it would draw way too much power from the battery.
