Customer Questions and Answers for Thermal Fuse (Disposable, One Time Fuse) by Whirlpool

Hello Nancy, What the technician who answered your first question meant is that if you disconnect one wire from the heating element, you can determine which leg of voltage has been dropped,(L1 or L2). This can be invaluable information when no obvious signs of failure are present such as a burned element, wire, or open thermostat. When you use the wiring diagram provided on the appliance, (usually in the console or in a plastic bag inside the kick panel or inside the cabinet under the main top), knowing which leg has been dropped can lead the technician to the failed component. Usually, when the easily accessed components test good, the problem will turn out to be a timer or a centrifugal switch that is made in the motor assembly. When testing like this, you should be very careful as there are electrical shock hazards around every corner. Also you should use ground as a test reference point. If you read 120Vac on the wire you disconnected to ground, test to the terminal it was removed from and there is supposed to be the other leg of 120Vac present at that point. Using this as a starting point, you can use the wiring diagram to trace the circuit back to the failed component. When you test on one side and get no voltage to ground, then go to the other side of the failed component, the voltage will disappear. Normally if the thermal fuse is bad, the unit will not start and run even with no heat.