How to Replace a Dishwasher Thermostat

What the thermostat does

The dishwasher thermostat is a temperature-sensitive switch that monitors water temperature. When the water reaches the set temperature, it opens or closes a circuit that controls the heating element. This keeps the wash water hot enough for detergent to activate and for sanitization. ENERGY STAR notes that certified dishwashers boost water temperatures to 140 degrees Fahrenheit for better disinfection.

If the thermostat fails open, the heating element never gets power, and the dishwasher washes with cool water. A related thermal fuse may blow if the thermostat fails closed, causing overheating. Replacing the thermostat is a common repair for a machine that no longer heats or dries properly.

Signs of a failed thermostat

Symptoms include dishes coming out cool and wet, longer cycles, or an error code for heating. Before blaming the thermostat, check the heating element, the thermal fuse, and the door switch. Also verify your home's water heater is set high enough, since incoming cold water will make the dishwasher struggle.

If the element has continuity and the problem persists, the thermostat is likely bad. On many models it sits next to the element, so you may want to replace both if you are already inside. See our heating element replacement guide for details.

Tools and safety precautions

Always unplug the dishwasher or turn off the breaker before working. Shut off the water supply valve under the sink. You will need a multimeter, screwdrivers, needle-nose pliers, and a flashlight. Have a towel ready for any water in the base.

Never work on the thermostat while the machine is live. The thermostat is in the high-voltage circuit. If wiring looks melted or you are uncomfortable, call a professional. For help understanding modern dishwasher features, see our built-in dishwasher guide.

Locating the thermostat

Remove the lower access panel (toe kick) held by a few screws. The thermostat is usually clipped to the heating element flange or mounted on the circulation pump. It has two wire terminals and often a reset button. In drawer dishwashers, like Fisher & Paykel, it may be behind the lower spray arm.

If insulation covers the area, move it aside carefully. Trace the wires from the heating element to identify the thermostat versus the thermal fuse. The thermostat is larger and may have a reset button.

Testing the thermostat

Disconnect the wire terminals from the thermostat. Set the multimeter to continuity or resistance. Place probes on the two terminals. A closed thermostat reads near zero ohms; an open one shows OL. Press the reset button if present and test again.

If the thermostat reads open, it is bad. If it reads continuous but the dishwasher does not heat, check the heating element and the control board. Also consider a heat-related test, which is beyond basic repair. For more fault diagnosis, see the dishwasher not heating water guide.

Removing and replacing the thermostat

Remove the retaining clip or screws that hold the thermostat. It may require a gentle twist to break the seal. Compare the new part with the old one to confirm the shape and mounting. Install the new thermostat so it sits flush against the heating element or pump housing.

Reconnect the wire terminals, ensuring they click into place. Tug gently to verify they are secure. Replace any gasket or insulation, then reinstall the access panel.

Testing after the repair

Turn on the water and power, then run a short cycle. After a few minutes, open the door and check that the water is warm. If the water does not warm, recheck wiring and the heating element. A thermometer can confirm the temperature reaches the expected range.

If error codes reappear, see the error code guide. If the unit trips a breaker, unplug and recheck. If you are not confident, call a technician.

When to repair versus replace

A thermostat replacement is inexpensive and takes about an hour. If the dishwasher is otherwise in good shape, it is worth doing. However, if the machine is more than a decade old, has a leaking pump, or a rusted tub, consider replacing it. New ENERGY STAR models use less water and energy, saving money over time.

If you decide to replace, see our best built-in dishwashers or best 24-inch dishwashers for current options. Consider the age and condition of the dishwasher before deciding; a new ENERGY STAR model saves water and energy over its lifetime.

What to pick for your dishwasher repair

Questions

Where is the thermostat located on a dishwasher?

On most built-ins, it is behind the lower access panel, clipped to the heating element or on the pump housing. On drawer models, it is near the heater after removing the lower spray arm.

How do I test a dishwasher thermostat with a multimeter?

Disconnect power, remove the wire terminals, and set the multimeter to continuity. A closed thermostat reads near zero ohms; an open one reads OL. Press any reset button and test again if open.

Can I replace a dishwasher thermostat without draining?

Yes, but shut off the water supply and disconnect power. Have towels ready for residual water. You do not need to drain a recently opened empty dishwasher.

Why does my dishwasher have a thermal fuse and a thermostat?

The thermostat regulates temperature; the thermal fuse blows if the heater runs too hot. A stuck-closed thermostat can cause the fuse to open, so check both.

Does a bad thermostat cause a leak?

No. Leaks come from gaskets, pumps, or hoses. A thermostat is an electrical component.

How long does a thermostat replacement take?

30 to 60 minutes for someone with basic tools, including time to test, remove the old part, install the new one, and run a test cycle.

Can a dishwasher thermostat be repaired?

No. It is a sealed switch. Replace it with a part matching your model. Pressing the reset button may work if it tripped, but if it reads open, replace it.