A vehicle electronic system having an electronic controller and a power switching device configured to switch between a first power setting and a second power setting. The first power setting includes powering at least one of a plurality of electrically powered accessories with power from an on-board electric power supply. The second power setting includes powering the at least one of the plurality of electrically powered accessories with power from an external power supply thereby preventing the use of electric power from the on-board electric power supply. The electronic controller is configured to electronically operate the switching device to switch between the first power setting and the second power setting such that in response to detection of power from the external power supply, the switching device is switched to the second power mode.