How To Test A Thermal Fuse

by Liz Gonzales

Have you ever faced any situation when a short circuit blew out the thermal fuse? Well, the thermal fuse blows if it gets too hot. There are few methods you need to know how to test a thermal fuse. So don’t worry. Here we will explain some testing methods of a thermal fuse.

A thermal fuse tends to interrupt the circuit if the temperature rises to a very high level. The circuit breakers detect overheating from fire, short courses, or unusual electronic operation. In this case, a thermal fuse tends to prevent an electrical accident. Depending on the types of thermal fuses, the methods also differ.

Besides, you have to know if a thermal fuse has blown or not. Today we will talk about various methods of testing a thermal fuse. So let’s begin.

Types Of Thermal Fuse Holders

Types Of Thermal Fuse Holders
Types Of Thermal Fuse Holders

Thermal Fuse Holders tend to hold a fuse. But they have variations in style and uses. Take a peek at this table.

Types Uses
Thermal fuse Clips Printed circuit board or panel
Panel Mount Thermal Fuse Holders Used for mounting into a dash or panel
In line Thermal Fuse Holder To connect with wiring
Thermal Fuse blocks and Bases Generally used for screw mounting to panel

Uses Of Thermal Fuse

  • We use thermal fuses mostly in our home appliances like coffee makers, dryers, toasters. These need to be very safe to operate. Thermal fuses make sure to cut off the switches if these produce overheat. So it will prevent that equipment from catching fire. If overheat produces, the thermal fuse will disconnect from the main switch.
  • The very common uses of thermal uses are hairdryers and cloth dryers. Some blow dryers tend to have a thermal switch, and it will turn off the dryers if it gets too hot. At the same time. It will help the dryer to cool down.
  • On the other hand, your electronic equipment will not heat the air inside the drum if you use it next time. So if it’s damaged somehow, then you have to replace it with a new one. But to do that, you have to know how to test a thermal fuse.

Functions Of Thermal Fuse

Functions Of Thermal Fuse
Functions Of Thermal Fuse

We use thermal fuses in home appliances as well as in industrial applications. You must be wondering how does it function?

Also Read: Best Watt Meter

Well, the simple thermal fuse has an internal sensor. Moreover, it is preset to its highest acceptable temperature. The sensor tends to monitor the temperature.

So if the heat reaches or exceeds the fixed preset level, the thermal fuse will automatically break off the electrical circuit. So eventually, it will shut down whatever machine you are using.

In this way, it will prevent catching fire or any major electrical accident. The fire won’t break out even if the lint trap is clogged.

On the other hand, people even tend to use appliances, and commercial machines use thermal switches. Metal contacts, gas mercury, and other mechanisms can be used for making thermal switches.

Checking Thermal Fuse If Its Blown Or Not

We know that a thermal fuse is a safety device, and it turns on the circuit against overheat. It tends to detect overheat, and it’s caused by short circuit or component breakdown. But you must be wondering how to test a thermal fuse. But for that, you have to know if it has blown or not. So for that, you have to learn some techniques.

To check if your thermal fuse has blown or not, you will have to touch the right side of your multimeter. It generally tends to lead to the right side of the fuse. Then it will repeat with the left multimeter lead. So if you see the multimeter is not moving, then it’s inevitable the thermal fuse has blown.

Thermal Cutoff And Thermal Fuse

Thermal cutoff and thermal fuse aren’t the same things. Suppose your dryer’s thermal fuse has blown. So how will you check that? The fuse tends to control the dryer’s heating element. On the other hand, the cutoff tends to control the motor. If the fuse blows, the dryer may not get hot. If the cutoff blows, the Tumblr may not spin.

However, the location of the cutoff differs from dryer model to model. But it’s generally attached to the dryer housing. It checks the temperature inside the housing. If the temperature crosses its limit, the thermal fuse melts.

Testing Thermal Fuse With a Multimeter

Well, you must be wondering what’s the fastest process of how to test a thermal fuse. Well, testing with a multimeter is one of the most rapid methods. Hence, you can take it into your consideration. So,

Location Of The Thermal Fuse

So first, you have to locate the fuse. You may find thermal fuses on the dryer’s exhaust conduct. In this case, you have to remove the dryer’s back panel to get into the fuse. But make sure you switch off all kinds of electrical power to the dryer before starting any method. Mostly we can see dryers plug into a 220-volt wall outlet. That’s why you have to unplug the unit to cut off power.

Measurement Of Thermal Fuse

If you check the thermal fuse with an electrical multimeter, then it’s very convenient. Because you will be able to find out if the fuse is functional or not. A thermal fuse is connected with it with two wires. So, you must set the multimeter to its lowest RX setting. Then you have to remove the wire from the fuse itself.

After that, connect the multimeter probes to each of the wire terminals on the fuse. If you see the reading of actual infinity, then it’s functioning correctly. But if you do not see that or something less than that, then there is an error. You must replace the thermal fuse.

Testing thermal Fuse With Digital Multimeter Reading

A Digital multimeter is a great piece of equipment to test a thermal fuse. By using it properly, it will give you accurate results.

  • So if the reading converts to a low resistance value, then the fuse is okay.
  • The fuse is blown when the reading is not changed. It will display the original 100% resistance state.

Testing thermal Fuse With An Analogue Multimeter

It is one of the primitive methods. You will see the reading by moving a needle over a fixed scale. So, select the Ohms range. Then touch the metal tips together. You will notice the needle sweeping across the scale. It will show little to no resistance. Showing 100 % resistance means the fuse is blown.

Testing A Thermal Fuse Without A Multimeter

The most convenient way to test a thermal fuse is to use a multimeter. What if you do not have a multimeter. It means you can test a thermal fuse without a multimeter. But it may turn out very unsafe and challenging. Don’t get scared. If you are too careful while applying the bypassing method, then it will work anyhow. But it will not cause significant injury or damage to you.

So you have to find out the location of the thermal fuse. Because it’s very important to conduct the process, you will see that a thin strip of white plastic is wrapped up with a wire coming out of each end. If you want to bypass the thermal fuse properly, join the two ends of the wire very carefully. You can use electrical tape for that.

After doing this, consider that you have finished your work. Then try to operate the dryer. If it works fine, then your job is done. But do not generate heat for not over 90 seconds.

Replace The Thermal Fuse

If the thermal fuse causes too much trouble, then you may need to change that. In this case, you need to buy a new thermal fuse.

Buy that kind of thermal fuse that matches your dryer or your equipment. Then place the thermal fuse into that space where the old one came. While doing that, you have to be very careful. However, there is the slightest possibility of occurring any major accident.

If you think of doing that, then you can take it to your local shop. But you should never attempt to operate your dryer without fixing your thermal fuse. It may lead to more severe damages.

Repair Tips Of Thermal Fuse

After testing the thermal fuse, you can even reset the thermal switch. We know that a thermal fuse is used to shut off the power of the heating equipment to prevent fire. If you see that your dryer is not warmed enough or it’s not turning on, then it may be blown. So you need to replace the fuse in that case.

  • The fuse is located in the dryer chassis with one or two Phillips screws. So you have to remove the screws and the fuse. Then place the new fuse and tighten the screws.
  • After that, you will reconnect the wires. To make sure if it’s working or not, you have to plug in the dryer. Then turn it on to see if it’s operating or not.
  • You can reset a thermal switch. But if your thermal fuse has blown, you have to replace it like an old-style electrical fuse.
  • Replacing a thermal fuse is very easy and inexpensive. But accessing the fuse may not turn out very easy. In most cases, you can get it, too, if you remove the front or back panel of the appliance.


Which home appliances have a thermal fuse?

Ans: Well, most people think cloth dryers and hair dryers have a thermal fuse. Any home appliance that tends to heat up has thermal use. Like -dishwasher, toaster, coffeemaker, microwave oven, standard electrical oven.

How will you know if the thermal fuse has blown?

  • Your device won’t be able to produce heat
  • Your device will not turn on
  • Even if you double-check and plug in the power cord, it will not work

How to conduct a continuity test?

Ans: First, you have to set the dial on a multimeter. So that you can measure resistance in ohms, then touch one probe to one of the fuse terminals and the other prob to the other terminal. However, note the reading. Suppose the meter shows 0 ohms, then it’s perfectly fine. You don’t need to replace the thermal fuse then. If it shows something more than that, then you need a new thermal fuse.



So, from the above discussion, you got a notion about how to test a thermal fuse. As you got to know, there are various methods of testing a thermal fuse. You can try thermal use by using a multimeter, or you can apply bypass methods.

Even if these methods don’t work, then you can replace the fuse and check. If you know all these methods, it will be beneficial for you. You can fix the problem all on your own. By knowing these methods will save you from unnecessary hassle. So if you face any problem regarding this issue, try out the different testing methods of a thermal fuse.

About Liz Gonzales

Liz lives in a suburb in New York city.
Both of her parents are the art professors at Sate University of New York.
As such, Liz grew up with all kinds of art objects, portraits, and books laying around the home.
Liz met up with Linea through another friend in some kind of online art forum. There great minds sparkled to take their passions onto the next level @

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