Samsung Microwave Fan Won’t Turn Off – Troubleshooting Guide

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Microwaves, even the best brands, can experience a series of problems. One of the more common issues is when the fan won’t turn off even after the oven has finished cooking. That can cause some concerns even though it may not affect how the microwave cooks your food. 

There are several reasons why a Samsung microwave fan won’t turn off. It can be either the thermostat or something wrong with the door switches. It could also be an issue with the control board or a problem with the fan itself. New microwaves use these parts to control the temperature and airflow. 

Read further to understand why your fan may be constantly running and how to fix the problem. 

How Fans Work with Temperature?

The purpose of the fan in the microwave is to keep the appliance ventilated. The fan draws in air through the appliance’s vents into the exhaust duct. This expells things like heat and moisture. 

The thermostat turns on the fan automatically when the appliance gets too hot. The fan will run until the oven temperature goes back to normal. While this may seem unusual, it is a perfectly normal operation. 

Sometimes, the vent fan will turn on even without you using the microwave. These are instances when steam hits the thermostat, causing it to start the fan. Typically, this happens after you’ve cooked something like pasta on your stove. Steam from the stove reaches the microwave and sets off the fan. 

This happens the most when the stove is placed below the microwave and steam rises to the microwave.

The door switches also work with the control board to control the microwave operations so if any of them go bad, you could experience a variety of problems including a fan that constantly runs. 

Read: How To Vent A Microwave On An Interior Wall

What To Do If Your Fan Runs Constantly?

You will always want to start with the simplest fix first. In this case, you want to see if the problem first is with one of the three door switches. Any one, or all, could fail and that could cause the fan to operate badly. 

Check to see if the fan continues to run with the door open. A running fan would indicate the problem is probably with the interlock switch. The switch allows the oven to operate. If it goes bad, the microwave and the fan can continue to run.

Another possibility is the microwave runs past its cook time even though the doors are closed.

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Pressing the “stop” button doesn’t do anything. This could mean the problem lies with the control board. 

Even with these possibilities, the first thing to check is the door switches. 

Read: Microwave Blown Fuse Symptoms

Door Switches

Most microwaves have three door switches that are installed for safety reasons. One of them failing will cause the symptom of an ongoing running fan. The first thing to do with door switches is to check them for grime and dirt. 

Make sure all the switches are clean to work properly. Open and close your door to see if it closes and opens properly. You should check to see if your microwave is under warranty if you want to get the door switches replaced. 

You can use a multimeter to see which switch has failed. To do that, you need to take the microwave door apart. That may depend on how handy you are with such things. 

Fan

A failed fan is the most common reason why it runs constantly. The specific problem will be with the exhaust fan motor. It will take some effort to see if the fan motor is defective.

You will need to remove the fan motor from the microwave. Be sure the oven is unplugged before you do anything. 

Once you get the fan out, turn the blades by hand. If they are stiff, the motor needs replacing. 

Use a multimeter to test the motor if the blades turn freely. Look for continuity. A motor that has no continuity or that has power but won’t run needs replacing.

Thermostat

The high thermostat sends voltage to the fan when the heat is going. A thermostat that has issues will continue to send voltage to the fan even after it’s cooled down to normal temperatures. 

You will need a multimeter to test the thermostat to see if it’s functional. 

Many times, an improperly running fan is associated with a failed thermostat. Some are more heat sensitive and that will cause the fan to start sooner and run longer than necessary. 

A temporary fix is to add a washer under the thermostat so air can move around it. This keeps it cooler, causing the fan to not run as long.

Getting a replacement thermostat isn’t a problem. It costs between $20 and $50. It’s a bimetal that turns to either have contact or end contact. It has two terminals attached to a round disk. 

The problem with replacing a thermostat is that it’s located in an awkward spot and requires the microwave to be uninstalled from any cabinetry. You will need to also remove the microwave cabinet and discharge the capacitor before doing anything. 

The capacitor is a highly dangerous element. Even with the microwave unplugged, the capacitor can store up to 4,000 volts and kill you with a shock. 

This is why most suggest taking your microwave to a certified technician to fix this type of problem. 

Read: Top Reasons Why Microwave Is Not Heating

The Control Board

The Samsung microwave oven control board has relays. These relays regulate everything about the oven including the fan circuits. It could be that the fan relays failed. 

A failed control board is rare so this is the least likely scenario. However, a symptom of a control board failure is the smell of burning electrical. If you smell that around your microwave, it is probably a control board issue.

Read: How To Fix SE Error Code On Samsung Microwave?

Are fans in microwaves effective?

Microwave fans are highly effective in removing contaminants in the kitchen air as long as they’re vented. 

The microwave hood recirculates air through charcoal filters before putting it back in your kitchen. The charcoal is a great filter to keep contaminants from re-entering the air and acts almost like an air purifier.

Can I fix my microwave fan myself?

Whether you can fix your microwave fan depends on your skill level and the tools you have. You may be able to fix the fan or the door switches but things like the thermometer and the control board may require a professional since it involves opening up to the capacitor.

Are microwave parts cheap?

Most microwave parts, whether it’s a thermostat or a fan motor, are pretty inexpensive and can be bought online. Most cost under $50. Be sure to buy genuine parts for your Samsung microwave because other generic parts may not fit with the Samsung model.

Will resetting help my fan issue?

Resetting your microwave helps with many issues and will clear any error that pops up. However, it won’t fix your fan problem because this is an issue that isn’t connected to an error message. 

A fan issue will likely require a part replacement like a fan motor, a thermostat, or a door sensor. 

Read: 5 Possible Issues When Microwave Turntable Is Not Turning

How do I reset my microwave?

If you want to try to reset your microwave and clear all errors, you can do that by simply unplugging it. Wait more than 60 seconds and plug it back in. Any error messages will be gone. 

You can try to use it again to see if the fan continues to have the same problem. What do I need if I call the Samsung Support Center about my microwave?

Most support centers require you have the model number of the appliance, your warranty information, as well as the date and place of purchase. Most of this information is in the manual that came with your appliance but you should have also kept either the receipt or record of purchase from your credit card or checking account.

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