Why Does Microwave Turn on When Door Opens? All You Need To Know

Before your microwave turns on, you should put it on or set the timer yourself. In some instances, this feature does not work that way.

When these features become defective, there is a cause for concern. A fault in the microwave can make it exhibit some features that are not only bizarre but also risky.

Have you ever noticed that your microwave automatically turns on once you open the doors? This fault is pretty common.

Your microwave can turn on when the door opens. This operation is due to a fault in the design. There may be a fault in the internal circuitry of the microwave. There may also be a glitch in the microwave’s systemic function or a faulty door. Whatever the case, you can find solutions to these problems.

In this article, I will explain all you need to know about why your microwave turns on when you open your door. I will also highlight how you can fix these problems when you notice them.

Is It Normal For a Microwave To Turn on When the Door Opens?

Why Does Microwave Turn on When Door Opens All You Need To Know

Having your microwave turn on when you open the door is not normal. The microwave is designed to work only when the door closes.

Within the microwave chambers, you have a component called the magnetron. The magnetron serves as an oscillator.

This oscillator emits some electromagnetic waves as it oscillates within the oven cavity. Electromagnetic waves are extremely small mediums of heat transfer.

These waves move in every direction because a stirrer propels these waves from the anode and cathode.

As the waves move in all directions, they hit the walls of the microwave but remain within the chamber.

The door serves as a lid which prevents the waves from going out of the microwave. As a result, the point where the microwave door latches on the hinge has a switch.

This switch is called the interlock switch. The switch is sensitive enough to put off your microwave when you open the door and switch it on when you close it.

Once this mechanism does not happen, the microwave has a fault. In some other instances, the microwave may have the inner light on.

With the lights on, the magnetron may be off. This feature does not necessarily indicate that the microwave is working.

The inner light can be on without the magnetron emitting the electromagnetic wave. This design is found in some microwaves, and it is not harmful.

3 Reasons a Microwave Turns on When the Door Opens

There are some reasons your microwave turns on when you open the door.

Some of the commonest reasons include the following;

  • Malfunctioning door switch 
  • Firmware glitch
  • Faulty internal circuitry

#1. Malfunctioning Door Switch 

Where the door latches to the body of the microwave, there is a switch. This switch affects the microwave by acting like a second off and on the button.

This mechanism was designed to prevent the magnetron from emitting electromagnetic waves when you open the microwave door.

When this switch begins to malfunction, the microwave can continue to work even when the door is open. 

Some microwaves have more than one door switch. These switches work in unison with the timer and the main switch.

Whenever these switches are faulty, your microwave will remain on after the door opens. These switches often become faulty because the door presses hard on them.

They can also get faulty if they become rusty and damaged by food debris or liquids.

#2. Microwave Firmware Glitch

The microwave is controlled by a system that coordinates every part and system that makes up the microwave.

This firmware works like the coordinating center in the microwave that holds every component together. These components include the timer, the main switch, and the door switch.

The coordination becomes distorted when the firmware experiences a permanent or temporary glitch.

This distortion causes your microwave to remain on when you open the door. In an ideal condition, the firmware switches the microwave off once the door opens.

Whenever there is a glitch, the whole microwave may begin to malfunction.

#3. Faulty Internal Circuitry

The electric circuitry of the microwave controls the flow of current to every part of the microwave. 

The microwave receives electric current from a source, and the connections transmit this current.

These connections make this electrical current travel in different directions within the microwave. These directions are either in parallel or in series.

When this circuitry becomes faulty at any point, the door can no longer switch off the microwave when you open it. 

How to Fix a Microwave That Turns on When the Door Opens

You can fix a faulty microwave door yourself. There are a few steps that you can follow to have all of these sorted out. 

Here are a few steps to follow:

  • Carry out a soft reset.
  • Perform a hard reset.
  • Replace the faulty door switch.
  • Call a technician.

Here is a brief description of how you can fix a microwave that turns on when the door opens.

Carry Out a Soft Reset

You need a reset when you are faced with the challenge of your microwave working when you open the door. 

This time, what you need to do is a soft reset. A soft reset can be the solution if the problem is a firmware glitch.

You can have a soft repair by pressing the reset button on the microwave panel. 

Perform a Hard Reset

If the soft reset fails to fix the problem, you may need a hard reset. There is no hard reset button on the microwave panel.

You will have to unplug the microwave and keep it standing for up to one hour. After this time, you can restart your microwave.

This method can fix a more severe glitch and a fault with the internal circuitry. 

Replace The Faulty Door Switch

In many instances, the door switch has a fault. What you need to do in this case is to replace the fault.

You can reach the microwave’s outer panel to find the door switch. There are usually up to three of them there.

These buttons sometimes may just be pressed down by a hard closure of the door, or they are rusty or lined by debris.

You may likely press the button, clean the debris, or oil the latch to remove the rust.

Call a Technician

In more complex cases, you may need to get the services of a technician. A professional who is well trained to fix all the faults.

Aside from fixing these faults, the technician can suggest ways in which you can use your microwave more effectively.

The table below combines the possible problems of the microwave door and how you can fix them.

Why Your Microwave Door Turns on Your MicrowavePossible Solutions
Malfunctioning door switchCarry out a soft reset, perform a hard reset and replace the faulty door switch.
Microwave firmware glitch errorCarry out a soft reset, perform a hard reset and call your technician.
Faulty internal circuitryCall your technician.

Why Does the Microwave Automatically Turn on When You Close the Door?

Sometimes, the microwave immediately turns on when you shut the door. This feature is not normal since it isn’t all the time the doors are shut means the chambers have food in them.

Here are some reasons why your microwave can come on when you shut the door and how you can fix the problem.

  • Control panel
  • Defective switch and board
  • Membrane panel
  • The faulty heat sensor panel

Control Panel

The control panel is where all the switches in the microwave pick up their instructions. When this panel becomes faulty, your microwave can turn on once you close the doors. 

You may need to contact a technician because this may be a complex problem.

Defective Switch and Board

When your microwave switch is defective, you may need to switch it off and take it off the power source.

This action will allow the internal circuitry to reconnect, and your microwave may return to its normal state. 

Membrane Panel

The membrane panel is located close to the control panel. You should unplug the microwave from the power source to access the membrane panel.

When you have taken off the power source, once you have gained access to the membrane panel, you can change it once you are sure it is a problem.

You can test for the viability of the membrane panel by the use of a multimeter.

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