1. Are you sure that the water heater in the rig is set up to heat water via either electric or propane?

2. If the switch to which you refer is for the gas heating, there should also be a red light next to or near the switch. This red light comes on when ignition is initiated and then goes out when the propane burner is working properly. In other words, if there isn't a red light next to the switch it may mean that the switch is for the electric heating element.

3. Have you contacted the manufacturer? They might know where they put/hid the switch in question. Any owner's manuals?

4. Often, manufacturers put such switches in or near the bathroom/shower area so that one can get the water up to temp prior to turning on the shower. If you've got an electric switch, it could well be in that part of the rig. It is possible that the switch is in the kitchen area, near the sink. I owned a travel trailer where the manufacturer had put the water heater electric switch inside a cabinet over the kitchen counter. If the rig has a panel area where the manufacturer has grouped holding tank level gauges, the thermostat and other device controls, such a switch could be in that area, but I'm sure you would have seen that.

5. I have seen units that have the switch outside, behind the door to the water heater. Take off the door and see if there is a little black switch on the surface of the water heater that faces out.

6. I doubt that any of this will help but not knowing the rig that's the best I can do. Hopefully someone with a 5th wheel like yours will respond.

Dutch and Garyjan, I did check the usual areas for obvious switches and at first look didn't see but the one switch inside the coach. The switch on the face of the heater is on and my niece-in-law told me that a technician explored under the sink which has a sheet of paneling concealing the heater. I visited the local dealer and got no help. I did get the phone # for the factory and have not as of yet called them. It's terrible to be so cute with their design of the units that the consumer can't figure out how to use some of the features. These switches (gas or electric) should be located together inside the coach near the holding tanks gages. 30 amps will heat the water if one turns off other electric devices. I turn mine off until I or the DW needs hot water and can turn the water heater on using the desired mode. This saves a lot of propane or allows for the electric heaters and this is done from inside the coach. The Grand Junction is a nice rig and I am having difficulty in accepting that just maybe Dutchman didn't consider this when designing this unit. Thanks to you guys for your input.