How Do I Know If My Dryer’s Thermal Fuse Is Blown?

If you own a dryer and it was made any time after the 1970s, it contains something called a thermal fuse. So, if your dryer was manufactured in the last 40 years, this component is part of what makes up your dryer. A thermal fuse is tasked with preventing the dryer from overheating. It’s an essential dryer part since overheating can lead to a fire that causes injuries or damage to your property.

The biggest issue is that the fuse sometimes malfunctions or stops working completely. This could mean that the fuse is blown, but it might also be related to another issue. You’re probably wondering how you can be sure of whether the thermal fuse is blown. The good news is that with a bit of troubleshooting and research, the process only takes a few minutes.

Signs That Your Thermal Fuse May Have Blown

In many cases, if your dryer has a malfunctioning thermal fuse, the dryer will not turn on at all. However, with some other dryers’ models, the drum will turn and the dryer will operate, but the heating element will not turn on to heat up the clothing inside the dryer. This could cause you to open up your clothes dryer only to find out that all of your clothing is still wet. Keep in mind that symptoms can vary by dryer model, even if two of them come from the same manufacturer.

Troubleshooting and Testing

As you know, the thermal fuse is a safety component focused on preventing fires. It’s found in dryers as well as a selection of other modern appliances that create heat. The thermal fuse ensures the dryer doesn’t get too hot by stopping the electricity flow before it can reach the heating elements. Since a thermal fuse that is no longer working can make an appliance fail to heat or can allow fires to occur, it’s essential to test the thermal fuse to make sure it is blown before you attempt a replacement. If you have suspicions that your dryer’s thermal fuse is blown, it’s best to stop using the appliance until the thermal fuse has been replaced.

Before you start the troubleshooting process, make sure the dryer is unplugged from all electrical sources first. Gas and electricity should not be connected to the dryer when moving forward with troubleshooting steps.

Take a look at the easy-to-use diagrams on AppliancePartsPros.com to find out where the thermal fuse can be found for your dryer. It is easiest to first search by model number, and reference the diagram for your specific model like this diagram  for Whirlpool model LER7646EQ2. Remember that dryers can have thermal fuses in various places, so the brand, model, and type all matter.

Now that you know where to find the thermal fuse, it’s time to find the correct panel so that you can access it. You’ll need to take off the appliance panel by removing the four screws in the corners that hold the panel in place. Once you have the panel removed, examine the components you can see and locate the fuse itself.

Trying a Bypass Method to Check on the Fuse

One of the options for testing the thermal fuse to see if it has burned out is by bypassing the device temporarily. The only issue with this method is that you might find yourself tempted to operate the dryer while in this mode. It’s also possible to forget that the fuse needs to be replaced when you see it works, and the dryer can run the way it should. These are things you need to avoid if you go with this method.

You should only bypass the fuse to determine whether it is working or not. It’s not something that should be used as a permanent repair. This process involves disconnecting the wires from the fuse and then tying them together using a jumper wire. After you have completed that, plug in the dryer and turn it on before checking whether it operates. If it starts running and has heat, this signifies that the thermal fuse has burned out and will need to be replaced.

Performing a Multimeter Test

What you’re looking for is a one-inch piece of plastic that has two wires attached to it. You can disconnect the cables on the thermal fuse by pulling on them gently. As with testing other electrical parts for continuity, a multimeter can be used for testing once the fuse is disconnected.

The first step here is to press the power button on your digital multimeter. Turn the control dial or press the button on the multimeter to test for continuity. Take the left lead on the multimeter and press it against the left side of the thermal fuse. The right lead should be placed on the right side of the fuse. Watch the needle on the multimeter for movement. If there is no movement, that means there is no continuity, and the thermal fuse needs to be replaced.

How to Replace a Dryer Thermal Fuse

Before you get started with the process of replacing the thermal fuse on your clothes dryer, you’ll want to be sure you have all the tools and parts that you need. So, get out your toolbox and make sure you have the following items:

  •     Work gloves to protect your hands during replacement
  •     A duct cleaning brush to keep everything tidy and neat
  •     A shop vac or vacuum cleaner for cleanup after the replacement
  •     A slotted screwdriver, also known as a flathead screwdriver
  •     A ¼-inch nut driver to help remove the mounting screw

This replacement should only take about 30 minutes to do even for a beginner. Make sure the power is off on your clothes dryer before you get started. This will keep you safe throughout the process to avoid electrocution.

  1. Make Sure the Rear Panel Has Been Removed If you’ve put back together your dryer after troubleshooting, you’ll need to take the back panel off again for the replacement. Pull the dryer forward closer to you and then remove the four screws in the rear panel. Once you have the back panel loose, you can remove it entirely and put it to the side.
  2.  Take Out the Thermal Fuse Take the wires off of the thermal fuse. Then use your nut driver to remove the mounting screw if one is attached. Once the cables are gone, and you have the mounting screw off, it’s time to take the thermal fuse out of the dryer. You’ll find it on the blower housing, and it should come right off so you can replace it.
  3. Replace with a New Thermal Fuse The next step is placing the new thermal fuse. Get it positioned perfectly and then secure it back on the blower housing with the screw you took off earlier. You’ll need to take the wires and push them onto the connection spades that you will find on the top of the new thermal fuse. Don’t worry about which wire goes on which thermal fuse terminal. It doesn’t matter which of them ends up where.
  4. Put the Back Panel Back on the Clothes Dryer At this point, you can place the back panel onto the back of the dryer again. Make sure that you line up the screw holes so it fits appropriately. Now all you have to do is place the mounting screws in the holes before using the screwdriver to tighten them firmly.
  5. Plug the Dryer Back In You now have a new thermal fuse in your clothes dryer, and the back panel has been reattached. The penultimate step is to plug the dryer back into the outlet. This will bring back electrical power to the dryer.
  6. Clean Out the Exhaust Vent Now that you have a brand new thermal fuse, you likely want to be sure that it doesn’t blow out again anytime in the near future. This last step will help you ensure that. What you want to do is take the flexible hose you find on the back of your clothes dryer and clean out the entire inside of the component. A duct cleaning brush can be used to remove any dust and debris inside. Once it’s clean, use your vacuum cleaner or shop vac to take up all the dust.

What is a Dryer Thermal Fuse?

Thermal fuses are used in your home appliances and for industrial purposes. The most basic version of the part encloses an internal sensor that has a preset to the highest temperature that is acceptable for the appliance to reach. When the monitored heat reaches that preset temperature, the fuse breaks the circuit to the electricity and shuts down the machine.

The purpose of any thermal fuse is to make sure the dryer doesn’t catch on fire if the exhaust is clogged or the lint trap is full, both of which can make it impossible for heat to escape. Some appliances use thermal switches rather than thermal fuses. These are made using various mechanisms such as gas, mercury, or metal contacts. The most significant difference between the two items is that a fuse is single-use. While thermal switches can also be made in a single-use style, many of them can be reset.

Thermal Fuses in Clothes Dryers

All of the modern clothes dryers on the market come with a safety component called a thermal fuse. This shouldn’t be confused with the cycling thermostat. The thermal fuse is a component with a single job – preventing overheating, which can cause fires. The fuse is similar to a switch since it can cut off the flow of electricity to the dryer if the temperatures get too high and a fire could occur.

Based on data from the U.S. Fire Administration (USFA) in the National Fire Reporting System (NFIRS), each year, there are around 2,000 residential home fires every year caused by dryers. These fires lead to $35 million in property damage, 100 injuries, and five deaths every year.

The most common cause of a fire is failing to clean out the lint trap. When lint accumulates in the exhaust ducts or the filter, it makes an environment that is ideal for fires to start. The hot temperature from the dryer can cause the fabric particles to combust, which may lead to a house fire. This is why it’s crucial to clean out the lint filter after every laundry load you do.

As noted, thermal fuses are single-use. That means that if they are tripped, they will need to be replaced. You can think of a fuse as a surge protector that absorbs energy to prevent fires and damage. After an accident where there are high temperatures, the fuse will not continue to work. It will need to be replaced to avoid fires in the future.

The good news is that the thermal fuse is easy to replace and relatively inexpensive to purchase. It’s usually one to two inches in length and will be found on the exhaust duct. However, different models of dryers will place the exhaust duct in various locations. After locating it, you can move on to troubleshooting and finding out where it is blown.

Wrapping Up

At this point, you know the symptoms of a malfunctioning thermal fuse and how to troubleshoot the issue. We’ve also shared how to install a replacement thermal fuse if the one in your dryer isn’t working correctly. Having this information can prevent you from having to replace an expensive dryer since the repair takes only a few minutes and basic tools you likely already have in your home. So, take that knowledge and see if this will help with your own dryer. You might be surprised how easy it is to switch out the thermal fuse and get your clothes dryer working again. As always, if you have any additional questions about working with your dryer thermal fuse, AppliancePartsPros.com is here to help.