An appliance diagnostic display and interface system providing a centralized user interface for appliance diagnostic information and control of system self-tests is provided. This centralized user interface is provided via an intelligent thermostat that includes an LCD display. The intelligent thermostat interfaces, via wireless or wired communications, with the appliances installed in the home. The intelligent thermostat then generates and displays various user interface screens that allow particular appliances to be selected. Separate appliance specific screens are then generated that allow the user to access the diagnostic information in system test functionality provided by the individual appliance. Soft function keys provided on the intelligent thermostat allow multi-functional access to the features of the invention depending on which screen is currently being displayed.