An electrical switch assembly for an electrical appliance having an electrical load such as a motor, includes a housing with an opening, switch terminals, and an on/off mechanical switching module. The switch assembly includes an electronic control module operable with a semiconductor switching device to control operation of the load, and a heat sink in thermal contact with the switching device for dissipating heat. The heat sink is electrically conductive and is in electrical circuit connection with a first terminal of the switching device and one of the switch terminals. The heat sink closes the opening and forms part of the housing.