How to Fix a Broken Microwave Exhaust Fan

When your microwave exhaust fan breaks it puts other parts of your microwave at risk for damage, which is why it is important to address this issue as soon as you notice it. There are a few parts in your microwave that could be damaged, resulting in an exhaust fan that doesn't work. To help you quickly diagnose your issue, we put together this guide with four common parts that may be malfunctioning and causing your exhaust fan to not work:


A dirty or clogged filter can cause several issues with your microwave, including an exhaust fan that won’t work. Whether you're using the standard grease-type filter or charcoal filter, you should be routinely inspecting them to ensure that they're clean and not damaged.

With the grease filter, you can remove it from the microwave and wash it in warm soapy water, allowing it to dry completely before reinstalling it.

For charcoal filters, you'll need to replace them if they are dirty or damaged. This style of filter cannot be cleaned and are designed to be replaced once they are dirty.

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If your over-the-range microwave is vented to the outside and the exhaust fan is not functioning properly, you may have a problem with the damper. The damper is located where the microwave meets the outside venting system.

To inspect it, you'll need to drop the microwave from its mounting position and visually inspect it. You are looking for signs of damage, warping, or a broken spring on that damper assembly. If it's unable to be repaired, you will need to replace it.

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Motor and Control Board

If your exhaust fan is not working at all, you'll need to inspect it to determine whether it's the motor or the controls that is causing the issue. To inspect the motor, you will need to remove the microwave from its mounting.

First, verify that the motor fan will turn freely. If not, you can assume that it is defective and will need to be replaced.

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If the fan blade does move freely, you'll need to check for voltage. This is a live voltage test, if you have not performed a live voltage test before, we suggest having a professional inspect your microwave. If the test shows there is no voltage present at that motor, you'll need to inspect the control board to determine if there is a loose/faulty connection, or if the board is defective and needs to be replaced.

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Happy Fixing

We hope that this guide helped you find the issue with your microwave! Do you need help with anything else around your home? Check out the entire blog for more repair advice and money saving tips!

If you need any of the parts mentioned above, or parts for any of your appliances, we’ve got you covered with over two million manufacturer-approved replacement parts!

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