It sounds from your description of the wall plate like you have a PowerTek TV power/controller (could be model RL-1003). This device disables power to the outlet when the ignition switch is on or when the motorhome is being driven. This is to disable the tv when underway so the tv is not viewable to the driver. It may no longer have the label on the front, but you can readily recognize it by the dark brown wall plate, and the small plastic box with several wires coming out the back. If you are working on this, please make sure the ignition is off.