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Microwave Fan Turns On When Door Opens | A Guide

A microwave oven is a straightforward appliance: it should heat and cook food without any fuss. To do that, a functioning fan motor is vital.

Microwave Fan Turns On When Door Opens

But what if you're encountering a fan problem?

If your GE microwave fan turns on or keeps running while you open the door, you might have a faulty door switch.

But don't throw your microwave oven out just yet! Learn how to repair a faulty switch and get your microwave working again in this article.

Microwave Fan Turns On When Door Opens [Case Closed!]

Microwave Fan Turns On When Door Opens [Case Closed!]
© Homesthetics - Monica Hewitt
The most common cause of microwave malfunctions involves the interlock switch of the door.

The interlock switch is connected to the door latch to ensure that the microwave oven only works when the door is closed.

When the interlock switch isn't functioning, the microwave doesn't recognize whether the door is open or closed.

This issue is relatively common, often caused by a faulty door switch.

To fix it, you will need to repair or replace the microwave door.


Unplug your microwave and ensure the capacitor isn't running before attempting to repair your appliance.

Faulty Door Interlock Switch

A microwave door tends to have two or three interlock switches that enable uninterrupted functioning.

A proper door switch activates power to the other microwave components and interrupts power when the door is opened.

The interlock switches are attached to the door latch. Metal prongs connected to the interlock switches detect whether the door is open or closed.

In case of an open door, the prongs are responsible for ensuring the microwave does not turn on. As a result, a faulty door latch can mess up the interlock switches' mechanism.

The primary issue with this kind of malfunction is that the interlock switches remain pressed even when you open the door.

It means that when the door opens, the lamp relay closes to turn on the light AND the fan. Usually, only the light should be triggered.


A faulty door can result in burn injuries for microwave users and can even affect nearby electronics.

Heat-Sensitive Switches

Some microwaves have switches that are heat-sensitive.

Even trace amounts of heat from your hand or other appliances can trigger the switches.

To prevent this, keep your faulty microwave away from potential heat sources (e.g., stoves, hotdog rollers) and use a cold object to press the buttons.

If this method resolves the problem, then heat may be the cause. Otherwise, it can be a different issue altogether.

How to Fix Your Microwave’s Fan

How to Fix Your Microwave’s Fan

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A faulty switch is the leading cause of a malfunctioning fan. As such, you will need to fix the microwave door to solve the problem.

To repair the door, you will need to replace the switch.

Refer to your microwave oven's manual to see where each component is.

Clean Your Door Switches

Before you attempt to repair anything in your microwave, make sure to unplug your unit to minimize injuries.

First, you will need to look into your door switches. Check the general condition of the door switches to see if there's any grime, debris, or grease.

Most people don't clean this part of the microwave when it gets dirty.

Combine water and a mild cleaner and sponge the door switch down to clean the switches.

Replace the Door Switch

Replace the Door Switch

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You can also repair a faulty door by replacing the switch. In some cases, you may have to get multiple switches replaced.

Be careful with the electrical parts and discharge the terminals of the high-voltage capacitor before you begin disassembling.

Take Note:

A microwave can still shock you even if it's unplugged!

Follow this guide if you plan on replacing or fixing your faulty door switch at home:

What You’ll Need

  • Screwdrivers with different bits
  • Replacement switch
  • Extra switches
  • Optional silicone spray

Step-By-Step Guide

  • Remove the cover at the top of the microwave. Don't attempt to open up parts of the door since you don't need access to that area.
  • Disassemble the mounting screws of the control panel and circuit board using the screwdriver. Check the microwave's manual to know which screwdriver to use.
  • Take out the panel covering the control board or the keypad. The circuit board, which controls the microwave, lies behind this panel.
  • Unscrew the screws of the front electric panel to access the switch assembly. You can find the switch assembly between the control panel and the hollow of the microwave.
  • Depending on the model, you might find multiple switches. GE microwaves typically have a monitor switch and two more relay door switches.
  • Carefully remove the switches with black ends from the switch assembly.
  • To find the faulty door switch, test each button by pressing on them.
  • If the button sinks down and gives a click, then it's working. But if the switch remains flat, you'll have to find a replacement.
  • Remove the old switch and install a new one when you've found the faulty part. Identify the exact model, buy, and install it.
  • To install the new switch, attach it to the wire connector and snap it until it fits.
  • Ensure the switch is aligned to the frame as you secure it with screws.
  • Place the control panel back and reassemble the parts back. Simply reverse the process to replace everything.
  • Plug the unit and test whether it is functioning correctly by heating room-temperature water.
  • Open and close the door to check whether the fan and the interior light are functioning correctly.
  • You know you've fixed your microwave when the fan no longer runs while the door is open.
  • If it still turns on even with the door open, there might still be issues with your unit.

Contact a professional or contact customer services if the same issue persists.

How Does a Microwave Fan Work?

Much like other electrical components of a microwave, the fan gets triggered when the door latch connects with the switch.

A faulty door switch can affect the functionality of the fans.

Most microwave models in the market have two fans. There's the vent fan that filters out the steam from the stove of the built-in microwave.

There's also a cooling fan circuit on the right-side panel that regulates the temperature of high-voltage components.

Look for the Fan Motor

You can find the motor below the oven lamp.

Most modern microwaves, like a GE microwave, have three switches.

The primary interlock switch (bottom switch) and the lamp relay on the control board need to be closed for the motor to work.

Microwave Fan Is Running FAQs

  • Below are related questions about malfunctioning microwaves:

  • Why Does My Microwave Fan Turn On by Itself?

    If you notice your microwave automatically running without your intervention, it’s most likely due to the change in temperature.

    Your microwave may have a built-in thermostat that detects temperature changes that can be harmful to your unit.

    It will set off the cooling fan and keep running until your microwave cools.

  • Is it Safe for My Microwave Fan to Turn On when the Door Opens?

    A microwave that’s running when the door is open is a potential health hazard because it emits microwave radiation.

    Exposure to high levels of microwave radiation can cause painful burns.

    However, if only the fan is on, it should be fine, as it’s a different operation with a separate switch.

  • Microwave Fan Turns On When Door Opens Conclusion
    © Homesthetics - Monica Hewitt


    If your microwave is malfunctioning, it might be a case of faulty switches and latches.

    The switch may be pressed permanently, causing different electrical parts of the unit to turn on automatically.

    Repairing the microwave yourself is doable and convenient! Just be careful when accessing each component, and keep your unit unplugged.

    But if you'd rather have a new microwave, check out this article on what size microwave you need for your kitchen.