Nicholas I read your last message. Thanks for the lint trap for my Whirlpool model #WED5560SQ0. The bias heater? Is that on the operating thermostat? Because of what you said about the heater getting bypassed on the thermostat it sounds as if that's what gives the dryer selector switch, model # WP3399640, it's high setting resistance. Is that true? Because we thought there was another resistor inside the selector switch to give the high setting. All our wires on the thermostat and thermostat heater, bias heater, are working fine and got continuity, by the way, including the wires on the selector's wire harness to the timer.
Answer Nicolas, the cycling thermostat has a built in heater that adds a small amount of heat to the thermostat when it is in a delicate or low heat setting. This makes the thermostat open up a little quicker to turn the heater off, thus allowing the heat to stay at a lower temperature. It is also referred to as a bias heater. Read More... Answered by AppliancePartsPros.com | Monday, December 24, 2018