You probably use your microwave on a daily basis, and you need it to work properly. If your microwave is not working as it should, this can be incredibly frustrating. Fortunately, there is a way for you to fix this issue, getting your microwave back on track once again.

If there is a problem with your microwave running with the door open, there are two possible problems. The first is that there is an issue with a door interlock switch. This means that even though you open the door to your microwave, the microwave thinks it is closed. If this is not the problem, then there could be an issue with the smart board. This is also called the control board.

Regardless, it is important to fix this issue if you would like your microwave to work properly once again. We understand that it can be a challenge to go through these issues, and we have done a significant amount of research to help you. Take a look at what we have uncovered, and see if you can get your microwave working again.

Are you ready to put a stop to your microwave problems? If so, then let’s dive right in.

What You Will Need To Fix Your Microwave

If you want to figure out why your microwave is running with the door open, you need to gather all your supplies first. You will certainly need access to your microwave. You will also need to have your manual so you can figure out where all of these individual parts are located.

In addition, you will probably need a multimeter and a screwdriver as well. This is important for disassembling your microwave if you have to. The multimeter is used to check the amount of electricity flowing through certain components of your microwave. 

You might also need a cleaning solution, a can of compressed air, and a microfiber cloth. This is important for cleaning the individual components of your microwave.

After you have gathered all of these materials, it is time to head over to the microwave to see what is going on.

How To Fix the Door Interlock Switch in Four Steps

If you are interested in testing the door interlock switch, there are four steps you need to follow.

Before we dive into this, you need to understand how the door interlock switch works. The interlock switch is important for providing power to the other components because it lets the microwave know that the door is closed and is ready to operate. If the components stay on when the door’s open, this is a sign the door interlock switch is sending an inappropriate signal to the rest of the microwave.

There are several steps you need to follow if you want to fix the door interlock switch. These include: 

#1 Disconnect the Power to the Microwave

Before you start working on the door interlock switch, you need to disconnect the power to the microwave. You need to make sure you will not get electrocuted if you are working in the microwave. Even though you may think you have turned off the power to the microwave, it is always better to unplug it completely. 

This step is relatively straightforward. The power cord comes out of the back of the microwave. Follow it to the outlet, and disconnect the microwave from the outlet. 

#2 Remove the Door Interlock Switch

After you have removed power from the microwave, you need to remove the door interlock switch. You should take a look at the manual to see where the door interlock switch is located. Usually, it is located relatively close to the door latch.

You may need a screwdriver to remove the door interlock switch. After you have taken out the door interlock switch, set it to the side. Remember to leave your microwave unplugged during this process. 

#3 Test the Door Interlock Switch

With the door interlock switch resting on the counter, it is time to test it using the multimeter. The multimeter is designed to test the amount of electricity flowing through the door interlock switch. If there is not a lot of resistance flowing through the door interlock switch, this is a sign that you need to replace the entire switch.

Take a look at the instructions for the multimeter. Typically, you need to bracket the part you are testing using the multimeter. Make sure you have a firm grip on the door interlock switch, follow the instructions in the manual, and make sure you test the amount of current flowing through the door interlock switch safely. 

A man testing the microwave with a multimeter tool
Use a multimeter to test the door interlock switch

If you get a number that is relatively close to 0, this is a sign that the door interlock switch is dead and it has to be replaced. If you get a number that is significantly above zero, this is a sign that the door interlock switch still has a lot of life. Therefore, you should be able to put it back in the microwave and have it work properly. 

#4 Replace the Door Interlock Switch (Old or New)

Finally, after you have figured out whether the door interlock switch is working, it is time to put it back in the microwave. If a door interlock switch still has life in it, you can put the old one back in the microwave. If the door interlock switch is dead, you will need to take a look at the manual, figure out what type of part you need, and order a replacement.

It is a relatively easy process to figure out if the door interlock switch is working properly. The part is usually located close to the surface, making it easy to remove and install. You simply need to see if the door interlock switch still has life in it using the multimeter. Then, you can figure out if you need to install a new door interlock switch or not.

How To Test the Control Board in 4 Steps

If the microwave stays on even when you’re pressing the stop button, there might be something wrong with the control board. This part is responsible for powering the individual relays. If the relay is not shutting off when the function is complete, this is a sign that you need to take a closer look at the control board.

There are several steps you need to follow if you want to test and replace the control board. These include: 

#1 Make Sure the Microwave Is Unplugged

First, you need to make sure the microwave is still unplugged. If you unplugged it during the last step, then it should still be unplugged. If not, you need to follow the cord back to the wall. Then, make sure you remove the plug from the outlet. This is critical for making sure you are safe when you are working on your microwave.

#2 Locate the Smart Board

After you have unplugged the microwave, you may need to remove the cabinet of the microwave itself to access the control board. Typically, the control board is found directly behind the keypad. You may need to access the top and bottom of the microwave, which is why you may need to take it out of the cabinet completely. 

A man repairing a microwave's control board
The control board is usually located at the back of the microwave’s keypad

Take a look at the manual if you are unsure where the control board is located. Based on the information in the manual, you should be able to identify and remove the control board. You need to do this to test it.

#3 Use the Multimeter

After you have opened up the control board, you need to test it using a multimeter. There are probably a lot of small parts that operate the control board, so you may need to use the manual to figure out where to put the multimeter.

After the multimeter is in place, test the amount of electrical current flowing through it. If you get a number that is close to 0, this is a sign that the control board is that and it has to be replaced. On the other hand, if you get a number that is significantly above zero, this is a sign that you still have a lot of life in the control board. 

#4 Replace the Smart Board or Microwave

Finally, once you know if the control board is the issue, you can put it back. If the control board is still working properly, then you do not necessarily have to replace it. On the other hand, if you got a number that is very close to 0, this is a sign that the control board needs to be replaced with a new model.

Unfortunately, it can be expensive to replace the control board of your microwave. Therefore, if this is the issue, you may need to get a new microwave instead. You might also want to reach out to a professional who can help you evaluate your options, figuring out what the best choice is. That way, you do not spend a lot of money replacing the control board of a microwave that is going to die in the near future.

Fix Your Microwave and Get It To Stop on Time

These are a few of the most important steps you need to follow if you are frustrated with your microwave. Your microwave is supposed to stop when you open the door, because this is an important safety step. If your microwave is not stopping as it should, you may have an issue with the interlocking door switch or the control board. You will need to use a multimeter to figure out what is going on.

If you do have to replace a part in your microwave, you may want to compare this to the cost of getting an entirely new microwave. There is a chance that it might be more expensive to replace the part in the microwave itself. Reach out to a professional if you have questions about how to handle this issue.