What Does A Blown 20 Amp Fuse Look Like?

Fuses are components built to protect electrical and electronic components from damage when a power surge, high voltage, short-circuiting, or any electrical issues in the car. Since these fuses serve as a shield over critical electrical components, they take fall for these components.

As a motorist or car owner, you’ll likely deal with blown fuses from time to time. These fuses have different amperages according to the component they are protecting. We have 5, 7.5, 10, 15, 20, 25, 30, 40, 50, and  60 amp fuses, and more.

But how will one know that these fuses have taken a fall for the component they are protecting? If you are among those asking what does a blown 20 amp fuse look like? This article will explain all you need to know about blown fuses. You’ll also learn what 30 amps, 40 amps, and other blown fuses look like.

What Color is a 20 amp fuse?

What Is A 20 Amp Fuse Used For?

As explained earlier, fuses protect electrical or electronic components from overload, invariably taking the fall for these components. It indirectly measures the current passing through and will blow if there’s a high current in the system. 20 amp fuses, along with other fuses, does the same job.

What components does the 20 amp fuse used to protect in cars? 20 amp fuses are typically used to safeguard the radiator fan, cigarette lighter, seat mechanism, wiper heating element, and AC blower motor.

For a 20 amp fuse to work effectively, it has to be a weak point between the car battery and the component they are safeguarding. For instance, if there’s a power surge traveling to the cigarette lighter, the metal strip on the fuse responsible for protecting it will cut, preventing electric flow from getting to the cigarette lighter and invariably protecting it from damage.

Note that the work of the metal ribbon across the two fuse metal poles is to transfer current from one metal pole to the other. If it breaks, it’ll prevent electric juice from passing from the first metal terminal to the second one.

Car manufacturers and aftermarket producers produce fuses with different capacities, sizes, and colors. For instance, a 20 amp fuse is yellow with ‘20’ inscribed on it. Others have different colors.

You can’t identify fuse amperage by the color alone because most car manufacturer now uses different colors on fuses. For instance, the 20 amp fuses on a 2019 Ford Ranger has a white, red, and blue color, different from the primary yellow color.

How Do You Test A 20 Amp Fuse?

Blown fuses prevent electric current from passing to the critical component they protect. However, this doesn’t mean the fuse is always responsible whenever the component stops working. The component can fail on its own while the fuse is still functioning. To determine if the fuse is faulty, you have to test it.

If you’re asking how to tell which fuse is blown in house or how to tell if fuse is blown in the circuit breaker, there are several ways to find out.

Visual inspection

Visual inspection is common with blade-like fuses like 5, 7.5, 10, 15, and 20 amp fuses. If you think your fuse has blown, check the metal strip that connects the two metal poles on the fuse. The fuse has a transparent glass or plastic cover. If the fuse is blown, you’ll see cloudiness in the glass or a broken ribbon on top of the two metal poles.

Sometimes, a blown fuse will not have cloudiness, but the metal ribbon will break. However, if you’re not okay with a visual inspection, check out the next method – how to tell if a 20 amp fuse is blown using a test light.

Using a test light

A test light is a vital electrical tool every electrician and mechanic should have. As the name implies, it is a tool used to test electrical components. If the component is in good condition, the tester will illuminate, showing there’s current on that circuit.

Here’s a simplified guide on how to tell if a fuse is blown; plug-in using a tester. Connect the tester wire to the negative battery terminal and touch the tester pin to the positive battery terminal. If it illuminates, you have a good connection.

Leave the tester wire on the negative battery and locate the fuse box in the engine bay and underneath the steering wheel. Start by testing the metal poles on the fuse. If the tester illuminates when you test both metal poles, the fuse is still okay. But if one terminal illuminates while the other does not, the fuse is blown and needs replacement.

However, if none of the terminals illuminates light, it does not mean the fuse is good or bad. It only means the electric flow is not getting to that fuse. For instance, most fuses will not come up until you switch on the ignition. So if you’re testing the fuse with the ignition off, it’ll not illuminate. Similarly, some fuses will not illuminate light until you turn on the engine.

Using a multimeter

The next option is using a multimeter. If you don’t have a tester or prefer to test your fuse with a multimeter, get one from a local shop or borrow from a friend. Connect the multimeter probes, touch them against each other, and record the readings.

After that, place the multimeter probes on the fuses and record the readings. However, you have to ensure the ignition is on or the engine is running, depending on what fuse you are testing. Swap the probes on the fuse terminals and see if it gives it the same reading. Typically, you should have the same reading.

Now, compare the readings when you touched the probes against each other with the last readings and see if it gives the same result. If the readings differ, the fuse is blown, but if you have the same result, the fuse is in good condition.

Follow the visual and tester approach if you’re wondering how to tell which fuse is blown in-house. The only difference between testing fuse in house and car is that the car battery supplies current when using a tester in cars, while the house power source supplies power when testing in the house.

How many volts can a 20 amp fuse handle?

What does a blown 20 amp fuse look like?

Whether you’re asking what does a blown 30 amps fuse looks like or what does a blown 40a fuse looks like, you need to understand that there’s no difference between blown 20 amps and other blown fuse amperages.

A blown 20 amp fuse will look like a discolored ribbon or strip with burnt marks. It’ll look like two metal poles with a disconnected ribbon across them. Depending on the severity of the issue, the plastic or metal casing may be damaged or cracked.

Regardless of the fuse size or amperage, they are similar. All fuses in the car fuse box have metal poles and a ribbon that connects them. When they blow, the ribbon melts or disconnects from the poles. The ribbons or wires that join the poles together are not hidden. So it won’t take long to detect when the fuse blows.

Final Words

This article has answered the question, what does a blown 20 amps fuse look like? Aside from explaining what a blown fuse looks like, you can easily tell a blown 20 amps fuse by simply looking at it or testing it with a tester or multimeter.

Lastly, diagnosing and replacing it requires a DIYer approach. You can do it with the right guide without any assistance. The replacement procedure requires you to remove the blown one with pliers and reinsert the new one. There’s no fastener to lose or bolt in.


Hi there, I am R. Hasan Tito, a mechanic, and owner of this website. My friend and I created this website to share our knowledge, expertise, and experience with our fellow mechanics' community and car users. I am a specialist and certified automotive mechanic (Both Heavy Commercial and Private Cars). I worked as a Mechanic and Mechanic Supervisor for over fifteen years at Global Rebound Automotive companies - Toyota, TATA, BMW, Nissan, TVs, and Others. Now, I enjoy my new role of leading a team of automotive experts (in their respective fields) and publish new content on a regular basis on my website and social media.

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