How to Test a Thermal Fuse

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What You'll Need

If a home appliance suddenly stops working, the first thing you should do is check if the thermal fuse is broken. You should always test the thermal fuse first before you go and purchase a new one. A thermal fuse is a safety mechanism inside the home appliance; it obstructs the flow of electric power in the case of overheating. It should take only a few minutes to test a thermal fuse.

Step 1 - Disconnect the Home Appliance

First of all, you need to disconnect the home appliance from the electric power supply. You can do this by removing the plug. Make sure that the home appliance has no supply of electricity before you start testing the thermal fuse.

Step 2 - Find the Thermal Fuse

Look for the thermal fuse located within your home appliance. Not all thermal fuses are located in the same part of the appliance. It may differ from one brand to another, and it may also vary depending on what type of home appliance you have. Generally speaking, the thermal fuse can be found in two locations: behind the rear panel or behind the bottom toe panel.

Step 3 - Uncover the Thermal Fuse

Use a screwdriver to remove the panel so that you can have access to the thermal fuse behind. If the thermal fuse is located behind the rear panel, remove the screws with the screwdriver. On the other hand, if the fuse is located somewhere in the front, use the screwdriver to press the metal clips and remove the panel.

You can find the metal clips very easily, approximately 4-inches from the panel’s edges. Put the panel aside when it comes loose, and leave it there until you have done all the testing and repairs necessary. The thermal fuse is a white strip of plastic, and it has two wires attached to itself. You need to remove these two wires.

Step 4 - Use an Ohmmeter

You need either an ohmmeter or a digital multimeter in order to test the thermal fuse. You have to adjust your ohmmeter to the Rx1 setting. If you are not familiar with an ohmmeter, this is a device that helps you check whether the thermal fuse is letting electricity flow into the system of your appliance or not.

Allow the probes of your ohmmeter or digital multimeter to touch the ends of the fuse. The device should display a reading on the screen. Read that carefully, and it will help you determine if the fuse is broken or not. There is no need to replace the fuse with a new one if the needle of your ohmmeter gives a reading of 0Ω. On the other hand, you need to install a new thermal fuse if the needle of the ohmmeter does not move.

Keep in mind that a thermal fuse cannot be adjusted, and if it is found to be faulty or broken, you need to replace it immediately.