Why Your Microwave Won’t Turn Off and How to Fix It

Put a stop to this frustrating problem

Woman setting microwave cooking time to heat her food
Photo: rh2010 / Adobe Stock
Woman setting microwave cooking time to heat her food
Photo: rh2010 / Adobe Stock
Highlights
  • When microwaves won’t turn off, the culprit is likely the control panel or the door switch.

  • It can cost between $20 and $300 to fix a microwave that won’t turn off.

  • If you’re not comfortable handling electrical components, hiring a pro is best.

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Have you noticed that your microwave won't turn off, even after the timer finishes? Whether it's the fan, light, or even the whole appliance, a microwave that refuses to power down can be frustrating and even a bit worrying. There are a few key reasons why this happens, and we’re going to dive into the most common problems and how to handle them. 

From faulty door switches to malfunctioning control boards, here’s how you can troubleshoot and fix these issues—or decide when it’s time to call in a professional.

Microwave Won’t Turn Off Unless Opened

One frustrating problem you may encounter is when your microwave keeps running unless the door is opened. Even when the timer has run out or the "stop" button is pressed, the microwave continues to operate. If this sounds like your situation, the issue likely stems from a faulty control board.

The control board is the brain of the microwave: It manages the functions and operations. When it’s damaged or faulty, the microwave might fail to receive the command to stop cooking. This means that the only way to shut off the microwave is to open the door, which triggers a safety mechanism to stop the appliance.

How to Identify and Fix the Problem

If you suspect the control board is the culprit, you can attempt to repair it yourself if you're comfortable with electrical components. Start by unplugging your microwave and removing the control panel. Once you've accessed the control board, inspect it for signs of damage, such as burnt or damaged circuits.

In some cases, the board can be repaired, but it often needs to be replaced entirely. The cost to replace a microwave control board typically ranges from $100 to $300, depending on your microwave model and where you source the parts. If you're not comfortable performing this task yourself, hiring a professional is always an option, but that will increase the cost to repair your microwave.

Microwave Won’t Turn Off Even When Opened

Tray with food inside of a microwave with the door open
Photo: avirid / Adobe Stock

If your microwave starts running when you open the door, or it continues to run even with the door wide open, then the problem is likely tied to the door switch. This switch acts as a sensor, signaling to the microwave when the door is open or closed. If the switch is damaged or worn out, it might send the wrong signals to the microwave, causing it to run even when the door is open.

How to Identify and Fix the Problem

To fix a faulty door switch, start by unplugging the microwave and accessing the switch, which is usually located near the latch mechanism. Using a multimeter, you can test the door switch to see if it’s functioning correctly. If the switch is faulty, you’ll need to replace it.

The cost to replace a microwave door switch is relatively inexpensive, ranging from $20 to $50 for the part.

Microwave Fan Won’t Turn Off

If your microwave’s fan keeps running long after you’ve stopped cooking, there could be a few reasons for this. The most common issues are related to overuse of the microwave, a faulty thermostat, clogged filters, or a problem with the control board. A kitchen with poor ventilation or high heat could also cause the fan to run excessively, as the microwave is trying to cool itself down.

How to Identify and Fix the Problem

To diagnose the issue, start by cleaning or replacing any clogged filters, as blocked airflow can cause the fan to stay on. If the fan still won’t turn off, you’ll need to test the thermostat or control board, as these components could be triggering the fan unnecessarily.

The cost to repair a microwave fan issue can range from $75 to $200, depending on the specific cause and whether parts need to be replaced.

Microwave Light Won’t Turn Off

If the microwave light stays on even after you’ve finished using the appliance, the problem is likely tied to the control panel, door switch, or bulb socket. In some cases, stuck buttons or a malfunctioning relay could also be responsible for keeping the light on.

How to Identify and Fix the Problem

To fix this issue, check the door switch and the control panel for signs of malfunction. If everything looks fine, test the bulb socket for power and ensure the light relay isn’t stuck. You might need to replace a damaged part, which can cost between $10 and $50.

Is a Microwave Dangerous When It Won’t Turn Off?

While modern types of microwaves come equipped with safety features, an appliance that won’t turn off can still pose some risks. Electrical issues can lead to overheating, which could damage internal components or even start a fire. Additionally, faulty microwaves can expose you to electrical hazards when attempting to repair them.

If you're not confident in your ability to troubleshoot the problem or you feel uncomfortable handling electrical components, it’s best to contact a local microwave pro. A qualified technician will ensure the job is done safely and correctly, helping you avoid potential hazards and get back to convenient cooking.

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