How to check if a car fuse is blown

If you’ve had your car for a while, chances are you’ll run into a blown fuse at some point. It’s one of those things that can leave even experienced drivers scratching their heads when dealing with car maintenance.

Car fuses are a key part of your vehicle’s electrical system. They’re designed to fail on purpose—cutting off the current when something’s not right. This helps protect your car’s components from overloads and can even prevent fires. So, how do you know if a fuse is blown, and how do you check? Let’s find out.

Understanding the Causes of a Blown Car Fuse

Most of the time, you won’t realize a fuse is blown until something in your car stops working. If your power socket, radio, or light suddenly isn’t working, it’s a good bet the fuse is the culprit.

A blown fuse can also affect your car's powertrain, driver-assist features, and safety features. For more critical components, like the ignition system, a blown fuse might trigger a warning light on your dashboard—or even prevent the car from starting altogether. Sometimes, you might even notice a faint burnt plastic smell, which can be a hint that a fuse blew recently.

How can you determine if a car fuse is blown?

Ideally, if you expect a fuse to have blown, you should bring your car in for a professional diagnosis. However, if you decide you want to check if you've blown a fuse yourself, here's how:

1. Find the fuse box

Depending on your car’s make and model, there could be up to four fuse boxes in different spots around the vehicle, so finding the one with the blown fuse is key. Your user manual is your best friend here—it’ll tell you which fuse box controls what circuit in the fuse diagram, making the search a lot easier. The most common places you’ll find fuse boxes are:

• Under the hood
• Under the back seats
• Beneath the dashboard
• In the trunk

2. Inspect each fuse

Once you’ve found the right fuse box, the next step is to remove the fuse box cover and pinpoint the bad fuse. Thankfully, most fuse boxes come with a handy diagram showing what each fuse does and where it’s located. If yours doesn’t have one, though, you’ll need to use a test light to track down the problem.

One of the easiest ways to check if a car fuse is blown is by using a test light. Start by turning the ignition on (but don’t start the engine). Then, clip the test light to any exposed metal on the car for grounding. Once that’s set, use the probe to touch both ends of each fuse. If the test light lights up on both ends of the fuse, it’s good to go. But if it doesn’t, the fuse is blown and needs to be replaced. Just keep in mind that a blown fuse might be a sign of a bigger issue, like a damaged wire, motor, or another component. If you’re going with the test light method, make sure to use a computer-safe one with an LED light.

Another way to test for blown fuses is with a multimeter. Place the two probes on opposite ends of the fuse—black on the negative side. If the reading shows zero or negative, the fuse is blown. To check another fuse, just repeat the process. It’s a quick and straightforward way to keep your car running smoothly! Just make sure you remove the fuse from the fuse box before testing it! Otherwise, you could accidentally damage the multimeter and end up with an even bigger problem.

3. Remove the blown fuse

Once the car is completely off, it’s time to remove the fuse. Use a fuse puller, which is usually stored right in the fuse box. If you can’t find one, a pair of needle-nose pliers or tweezers works just fine.

With the fuse out, hold it up to a light source while still gripping it with the puller. Look closely at the translucent part—you’ll see a thin metal wire inside. If that wire is broken or looks like it’s in two pieces, the fuse is blown and needs to be replaced with a new fuse. In some cases, you might also notice a dark metallic smear in the glass, slight warping, or even melting of the plastic case, which makes it even more obvious.

What causes a blown car fuse?

A blown fuse usually points to a short circuit due to damaged wires or faulty electrical components. This happens when an electrical component pulls more current than it’s designed to handle, often because something isn’t working properly. When an electrical circuit gets overloaded, it can overheat, melt, or even start a fire. This kind of failure can cause serious problems for both your car and its passengers. Fuses step in to stabilize the current and prevent these dangers. If a fuse blows, you might notice that your car struggles to start or certain electrical features just won’t work. Common culprits of blown fuses include defective switches, faulty wiring, or even mechanical issues with motors or moving parts.

For simple issues like lights, power seats, or air conditioning, checking the fuse is the first step. But if the fuse is part of a more complex system, it’s important to figure out why it blew in the first place. It could be a sign of a bigger problem that won’t go away even after replacing the fuse. To play it safe, consider consulting a certified mechanic or your dealership’s service department.

Learn more with BrokerLink

Wondering if your car insurance covers a blown fuse? Reach out to BrokerLink today. One of our licensed insurance advisors would be happy to answer any questions you have about car insurance, including what type of coverage you need to cover a blown fuse.

You can reach us by phone, email, or in person at any one of our locations throughout Canada. No matter how you choose to get in touch, a BrokerLink insurance advisor will be happy to assist you. We also encourage you to take advantage of our free online quote tool that can provide you with a competitive quote in minutes.

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