Is The Microwave Turning On When The Door Is Closed? (Fix It Now!)

Microwaves have become an integral part of just about any kitchen. So, when it is not working for any reason, it can be a worrisome endeavor. There are more than a few instances in which a microwave would stop working.

So what happens when it actually just won’t stop running? Sometimes the microwave can turn on the instant the door closes, but why? Well, the most likely explanation is an issue with the control board. Replacing it is the most common remedy, though it will likely take professional intervention to achieve.

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3 Reasons Why a Microwave Turns on When Door is Closed

A fully functional microwave is supposed to run only when you push the necessary buttons to do so. It should not, however, start running the second the door is closed. When that happens, it is a clear indication that something is not right.

Even if you keep pushing down on the “stop” button, the microwave does not stop. The clearest indication is that the control board is at fault. The issue tends to stop when the door is opened. That means that the switch is cutting off power like it should be.

Control board. If opening the door triggers the switch to turn it off, then it means one thing. That the control board is not sending the right signals to turn off power. It could also be an indication that one of the door switches is bad and not doing its job.

1. Microwave Also Runs When the Door is Open

Perhaps you have the inverse of the aforementioned problem where the microwave continues to run even when the door is open. Unplug the machine before performing any troubleshooting diagnostics. You are dealing with electrical current and should never mess with a running microwave.

When the microwave continues to run even when the door is open, the likely cause is a faulty door interlock switch. When the door latches into place, that latch connects to a switch. The switch activates and gives the microwave the signal that it is ready to receive power. When the switch is bad, the microwave will either stay active even when open or won’t work at all.

2. The Heat Sensor Panel May Be at Fault

Though less common than the aforementioned issues, there is another potential cause for the microwave turning on by itself. The heat sensor panel could be the faulty component causing this anomaly.

Some microwave buttons are actually heat sensitive. So sensitive that, even without touching them, the warmth from your fingers could be enough to “press” the buttons. So, it could be that the heat sensors are off and the heat from the microwave’s pan is turning it on. When the heat sensor is bad, it will need to be replaced and should be done by a professional.

3. Membrane Keypad

Though it is not quite so commonplace, there are some microwaves that come with what is known as a membrane keypad. The membrane could become faulty, leading to the microwave turning itself on even when there has been no action by the user.

To replace the membrane keypad, it may involve ordering a new control panel frame assembly. The new control panel frame assembly will have the membrane keypad already installed. Even better, it is generally simple enough to swap out that even DIYers can do it without professional intervention.

Replacing the Parts

Now that you have an idea of which problem you are dealing with based on symptoms, the resolution is fairly simple. The good news is that there are a couple of options to work with though they can depend on your level of experience.

Test continuity. Making sure that the microwave is unplugged, you can test the continuity of the switch or control board. Use a multimeter to check the continuity. You may find that the problem is not with that component and can move on to troubleshooting other issues.

Replacing the control board. If the control board is bad, then you will have to remove the outer cabinet to locate the control board. The control board is right behind the touchpad. If you test the control board and it reads fine, the issue could be with the control panel relays. In which case, then only the relays would need to be replaced.

Replacing the interlock switch. The interlock switch is generally in the same area as the control board. It is mounted near the touchpad to where the door and cabinet meet. Tougher to recognize, the switch is actually easier to replace than the control board. It is just difficult to find and remove the screws holding it in place.

Why you should call a professional. The simple fact of the matter is that microwaves can still hold a lethal charge even when unplugged. That means discharging the capacitor before proceeding to a fix. Without proper training, it is highly advisable that you leave this to a professional. They know how to proceed in the safest manner possible and can perform a more accurate assessment. Whenever an electrical current is involved, the utmost safety should be practiced.

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Related Questions

Of course, there are other issues that can arise when using a microwave. Moreover, there are other burning questions (pun intended) that people want to know when it comes to their microwaves. Here are just a few other frequently asked questions.

Is It Dangerous if the Microwave Runs with the Door Open?

Needless to say, you don’t want your microwave running with the door open. But is it actually dangerous to have it running while the door is open? The quick answer is “yes”, though the answer is a little more complicated.

If there are issues where the microwave runs while the door is open, you could be risking electrical shock. For that reason alone, you should unplug the microwave and call a professional or just get a new microwave.

That said, there are also microwave fields at play. If you are within a few inches of the oven cavity or open door, those fields could be enough to produce diathermy. Diathermy is warm sensations, particularly in your hands.

Those microwave fields also have radiation to them. With enough exposure, they can be particularly hazardous to the eyes and genitals, so don’t risk it.

Why Won’t the Microwave Keypad Work?

Another very common issue when it comes to microwaves not working is that the keypad buttons don’t function properly, if at all. There are two possible explanations, one pretty simple while the other is a lot less so.

The first explanation is that the buttons are simply too dirty to properly work. Over time, dirt and food can get into and around the buttons, making them unusable. Solving the issue is generally pretty simple. Use warm, soapy water and gently scrub using a non-abrasive cleaner. Keep working at it until the buttons start to work again.

The other solution is that the control board and keypad have loose connections. Depending on the brand of microwave, this can be a relatively easy fix. Still, it may be better to simply bring in a professional to do the job.

Why is My Microwave Sparking?

When you are just trying to heat up some food, the last thing that you want to see is a spark or electrical arc as the food cooks. There are also more than a few potential issues behind the sparking/arcing issue.

The sparking/arcing could be due to using a metal container, which is far more commonplace than you would think. It can also be due to excessive dirt in the microwave if it has not been cleaned in quite some time. The issue could also be due to a high voltage transformer.

Whatever the case, stop the microwave immediately and unplug it. You can try cleaning the microwave if it is exceedingly dirty and then trying it again. If the issue persists, consider bringing in a professional or simply replacing the microwave.

Why Won’t the Light in the Microwave Turn on?

From time to time, the microwave will work as it normally does but the internal bulb may not turn on when the door opens. It may seem like the obvious solution is to change out the light bulb and that is not a bad place to start.

If the problem persists even after the bulb has been changed out, check out the light socket or main control board. The board in particular can become faulty over time and either need replacing or repair to fix.

The socket. Check the light socket for potential damage that could prevent the bulb from lighting up. You may also want to use your multimeter to check the continuity of the socket itself. Should there be no continuity to it, then you will have to replace the socket entirely.

The control board. If the socket has continuity, then you can safely assume that the issue is with the control board. Replacing the control board can be a bit more difficult of a fix, so consider calling in a professional or simply replacing the microwave.

Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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