What Does the Thermal Fuse Do on a Dishwasher?

A thermal fuse protects a dishwasher from overheating. It is found in electronically-controlled dishwashers and located on the control board. If a dishwasher does overheat, the fuse trips and cuts off power to the control board. The machine shuts down and will not restart.

When a dishwasher fails to start, it could also be due to the thermal fuse. The device may sense a malfunction. The fuse needs replaced, but the source of the malfunction also needs investigated or the fuse will keep tripping. Items that can lead to a blown fuse include a malfunctioning timer, a faulty selector switch or the control board itself.

Thermal fuses are sold with or without a wiring harness. Professional installers advise replacing the wiring harness in case that is part of the problem. Homeowners with some repair skills can usually handle the repair. Disconnecting the power source is the first step.

To check for a faulty fuse, the inner door over the control panel is opened and the fuse removed from the wiring harness. A multimeter, which is a multipurpose electrical testing device, is used to check the fuse and harness. If the fuse and harness do need replaced, the brand and model number of the dishwasher are needed to purchase the correct parts.