Usual is the heater element, shorts internally, replace, If you have a test meter check it out 1st, But other wise, unplug the heater and then try it, if it runs heater faulty. Make sure that you unplug the unit, before pulling the wires off the heater, and make sure that the wires you take off cannot touch each other or anything else, insulating tape if you have any. Only other thing if not that is motor or control unit/timer
SD, January 2012
