A hot melt adhesive hose assembly has a hot melt adhesive hose core, and a pair of heater circuits wrapped around the external peripheral surface of the hose core. A first one of the heater circuits is electrically connected to the hose assembly electrical circuitry, and should a failure occur within the first one of the heater circuits, an electrical switch mechanism is actuated so as to effectively remove the first, failed heater circuit from the hose assembly electrical circuitry, and substantially simultaneously, electrically connect the second one of the heater circuits to the hose assembly electrical circuitry.