How to Fix a Microwave Oven Vent/Fan That Won’t Turn Off?

Microwave ovens are an essential appliance in most households, but when they start malfunctioning, it can be frustrating. One such issue that many users face is a vent/fan that won’t turn off. This can lead to excessive noise and energy consumption, and it can also be a safety hazard. In this guide, we will provide you with a step-by-step process to diagnose and fix your non-stop vent/fan issue.

Why won’t the microwave oven vent/fan turn off?

Before we dive into the solution, let’s understand why this issue occurs. The vent/fan in a microwave oven serves the purpose of dissipating the heat generated during cooking. When the cooking process is complete, the vent/fan should turn off automatically. However, if it doesn’t, there could be several reasons for this.

Causes of the non-stop vent/fan issue

The following are some of the common causes of the non-stop vent/fan issue:

  • Stuck switch: The switch that controls the vent/fan may be stuck in the “on” position, preventing it from turning off.
  • Faulty thermostat: The thermostat that regulates the temperature of the oven may be malfunctioning, causing the vent/fan to stay on.
  • Malfunctioning control board: The control board that manages the functions of the oven may be faulty, leading to a non-stop vent/fan issue.
  • Damaged motor: The motor that drives the vent/fan may be damaged, causing it to stay on.
  • Obstructed vent: If the vent is obstructed, the heat generated during cooking cannot be dissipated, causing the vent/fan to stay on.

How to diagnose the non-stop vent/fan issue?

Before you start diagnosing the issue, ensure that you unplug the microwave oven to avoid any electrical hazards. The following are some steps to take before diagnosing the problem:

Step 1: Check the user manual to understand the functioning of the vent/fan.

Step 2: Inspect the vent to ensure that it’s not obstructed.

Step 3: Check if the issue persists even after you have turned off the oven.

Once you have completed these steps, you can begin diagnosing the issue. Here are the steps to follow:

  • Using a multimeter to test switches and thermostats: A multimeter can help you determine whether the switch or thermostat is faulty.
  • Checking the control board for issues: If the switch and thermostat are functioning correctly, you may need to check the control board for any issues.
  • Examining the motor and vent: If the control board is not faulty, the issue may lie with the motor or the vent. Inspect these components for any damage or malfunction.

How to fix a microwave oven with a non-stop vent/fan?

Once you have identified the cause of the issue, you can start fixing it. Here’s a step-by-step guide for fixing the issue:

Tools and materials needed

Screwdriver, multimeter, replacement switch/thermostat/motor (if required).

Step-by-step guide for fixing the issue

  • Unplugging the microwave oven: Ensure that the oven is unplugged before you start repairing it.
  • Removing the control panel: Use a screwdriver to remove the control panel and access the internal components.
  • Inspecting the switch and thermostat: If the switch or thermostat is faulty, remove it and replace it with a new one.
  • Replacing the faulty component: If the motor is damaged, remove it and replace it with a new one.
  • Testing the new switch/thermostat: Once you have replaced the faulty component, use a multimeter to test whether it’s working correctly.
  • Reassembling the microwave oven: Once you have fixed the issue, reassemble the microwave oven and plug it in.

When to call a professional?

If you are not comfortable repairing the microwave oven yourself, it’s best to hire a professional. Here are some reasons to consider hiring a professional:

  • Lack of technical expertise
  • Safety concerns
  • Warranty issues

Tips for choosing a reliable repair technician:

  • Check if the technician is certified
  • Check if they have experience repairing microwave ovens
  • Read customer reviews
  • Check their pricing

Cost considerations

The cost of repairing a microwave oven with a non-stop vent/fan issue depends on the cause of the problem and the cost of the replacement components. On average, the cost could range from $50 to $300.

How to prevent the non-stop vent/fan issue from recurring?

Here are some simple maintenance tips you can follow to prevent the non-stop vent/fan issue from recurring:

  • Regularly clean the vent to prevent obstruction.
  • Avoid overusing the microwave oven.
  • Use the microwave oven as per the manufacturer’s instructions.


In conclusion, a non-stop vent/fan issue in a microwave oven can be frustrating and potentially dangerous. By following the steps outlined in this guide, you can diagnose and fix the issue yourself or hire a professional if needed. Remember to follow safety precautions and always unplug the microwave oven before attempting any repairs. Additionally, regular maintenance can help prevent this issue from occurring in the future. By keeping your microwave oven in good condition, you can ensure its longevity and continued efficiency.

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