How to Test If a Dishwasher Thermostat Works


It is possible that more than one symptom might be caused by a defective dishwasher thermostat. This is due to the fact that a dishwasher may have more than one thermostat. Because a high-limit thermostat prevents the dishwasher from becoming too hot, if it fails to do its job properly, the machine will turn off before the clean dishes within it have had a chance to dry after being washed. While the water temperature is being raised by the heating element, the temperature-sensing thermostat keeps the device off so that it doesn’t become damaged. Even if you’ve never had a look inside your dishwasher before, the procedure is simple enough for a first-timer to understand, so long as you exercise care while working with the electrical components.

  1. Stop the flow of energy to your kitchen appliances by switching off the power at the panel that controls the circuit. Take note that the circuit for the refrigerator could not be the same as the one for the dishwasher. Loosen the Philips screws that are located on each side of the kick panel that is located at the bottom front of the dishwasher. Place the screws in a secure location, and remove the kick panel from the dishwasher.

  2. To verify that the power has been turned off, use a noncontact voltage tester to check the wiring that is located beneath the tub of the dishwasher.

  3. Cast some light into the depths of the tub using a work light. Look for one or a pair of circular discs that are silver in colour, have a diameter of about 1 inch, and have two wires connecting to them. These are the controls for the thermostat. Pull the wires away from the terminals in a careful manner. Either use a tiny Phillips screwdriver to loosen the screws that are keeping the thermostat in place, or remove the thermostat clips, and then remove both the thermostat and the holder it is in.

  4. Check the temperature-sensing thermostat with a multimeter by touching one probe to each terminal or by adding alligator clips to them. This thermostat may be located in the middle of the tub; refer to the wiring diagram in your owner’s handbook for further information. Rx1 should be where the dial on the multimeter is set. Look for a number that reads “infinity.” Place the thermostat in close proximity to a warm bulb. The number on the display ought to become zero.

  5. Check the limiting thermostat, which could be on the right side of the tub. Perform the test in the same manner, but look for a reading of infinity when the temperature is normal, and a reading of zero when the temperature is high. If you have two thermostats and are unsure which one is which, you may confirm this by comparing the look of each thermostat as well as any embossed markings with the web catalogue of a repair parts shop.

  6. If the thermostat is broken, replace it, and then test it by putting a load of dishes through the dishwasher.

    Things You Will Need

    • Philips screwdrivers, medium and small

    • Noncontact voltage tester

    • Work light

    • Multimeter


    At the time of this writing, a replacement thermostat for a dishwasher may be purchased for a price that is less than $25.