A fuse is a small electrical safety device designed to protect your vehicle’s wiring and components from damage. Inside each fuse is a thin metal strip that melts when excessive current flows through it, breaking the circuit and preventing potential fires or damage to electrical parts and wiring.
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Think of fuses as the guardians of your car’s electrical system that are sacrificed to keep everything else safe. Your vehicle contains dozens of electrical circuits powering everything from headlights and power windows to the engine control module. Without fuses, a simple short circuit could send excessive current through these systems, melting wires, destroying expensive parts, or starting a fire. Fuses are an inexpensive and reliable way to protect these circuits.
Understanding the different car fuse types helps you maintain your vehicle properly and find the right replacement when needed. Here’s a breakdown of the most common varieties.
Blade fuses are the most widely used fuses in modern vehicles with a plastic housing that has two metal prongs. Standard blade fuses, both ATO and ATC, measure about 19mm wide, mini blade fuses are approximately 11mm wide, and micro blade fuses are around 9mm. Many newer vehicles use mini or micro fuses to save space to keep fuse boxes more compact.
Glass tube fuses were common in vehicles manufactured before the s. They have a glass cylinder with metal caps on each end, allowing you to see the metal strip inside. While generally replaced by blade fuses, you’ll still find them in classic vehicles, motorcycles, and some aftermarket accessories.
Ceramic fuses look like glass tube fuses but use a ceramic body instead of glass. They’re more durable and handle heat better, making them suitable for high-temperature applications and used more recently in European vehicles.
ANL and maxi fuses handle high-amperage circuits powering major components like the alternator, cooling fan, or aftermarket audio systems. Maxi fuses look like oversized blade fuses, while ANL fuses are large, flat, bolt-down pieces ranging from 20 to 200 amps.
Blade fuses use a universal color-coding system to indicate amperage:
Gray fuses are typically 2 amps
Tan is 5 amps
Brown is 7.5 amps
Red is 10 amps
Blue is 15 amps
Yellow is 20 amps
Green is 30 amps
The amperage number is also printed on the topside of each fuse. Always match both the color and printed rating when replacing fuses.
Your owner’s manual contains a fuse box diagram showing the location and amperage of every fuse. Many vehicles also have a diagram on the fuse box cover that identify which circuit each fuse protects, making troubleshooting easier. If you don’t have your manual, you can find fuse diagrams online or visit AutoZone for assistance.
Fuse replacement is a simple DIY task that takes just a few minutes:
Step 1: Turn off the ignition and all electrical functions.
Step 2: Locate the fuse box using your owner’s manual. Most vehicles have one under the dashboard and one in the engine compartment.
Step 3: Use the fuse diagram to find the fuse for the circuit you think is affected.
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Step 4: Remove the fuse using a fuse puller tool that’s often included in the fuse box, or needle-nose pliers.
Step 5: Inspect the fuse. A broken or blackened metal strip indicates it’s blown.
Step 6: Insert a new fuse with the same amperage rating and type.
Step 7: Test the circuit to confirm it’s working properly.
Keep these safety tips in mind:
Always replace fuses with the exact same amperage rating.
Never use aluminum foil, wire, or higher-rated fuses as substitutes.
Keep spare fuses in your glove box for emergencies.
If a new fuse blows immediately, there’s an underlying electrical problem that needs professional diagnosis.
Common symptoms of a blown fuse include a specific electrical system that’s suddenly stopping such as power windows, radio, or interior lights. When you’re inspecting a suspected fuse, look for a broken metal strip inside or dark discoloration. A multimeter set to continuity can confirm whether a fuse is good or blown.
Repeated blown fuses indicate a deeper problem like a short circuit or damaged wiring. Avoid overloading circuits by limiting devices plugged into auxiliary power outlets, and have aftermarket accessories professionally installed for peace of mind. You can also inspect your fuse box from time to time for corrosion or loose connections to prevent more extensive damage.
Whether you need a single replacement fuse or want to stock up on spares, AutoZone has you covered. Our friendly staff can help you find the exact fuse type for your vehicle and test your electrical system with free Fix Finder services.
My brother and I both work in vehicle repair, and he sure got my attention when he gave me a set of resettable blade “fuses” to try out. These devices are actually fuse-shaped circuit breakers, and my new kit of six breakers goes up to 30A in 5A increments—just right for most auto circuits. For professional vehicle repair, circuit breakers are not a long-term solution for a circuit that keeps tripping. The root cause of that issue must be found and addressed before the vehicle leaves your bay. So how else might a pro use these?
After messing around with these breakers for a little while, I’m glad to have them, but I’m also not swapping out all the fuses in my car to run breakers only.
Before getting into my favorite use cases for these, let’s take a minute to examine the differences between fuses and circuit breakers. A traditional fuse has a fuse element that permanently burns out to disconnect a circuit when amperage exceeds the fuse’s rated limit. That fuse cannot be reused, and a new one must be installed to restore circuit operation. In contrast, these micro breakers trip just like the breakers that are (almost certainly) in your home’s electrical panel. When the rated amperage is exceeded, the circuit is disconnected, but it can be reconnected by simply using the breaker’s reset to get that circuit back in business.
Although self-resetting breakers in blade-fuse-sized formats have been around for a while, I’ve never liked the automatic reset feature. A blown fuse or tripped breaker means there is a problem, and I would rather have manual control over any resets so that the circuit remains off until I’m ready. That’s why I’m recommending the newer manual reset style over the older “automatics” here.
Fuse size is another caveat here. At the time of writing, resettable breakers are only available for standard, maxi, mini, and low profile mini ATM blade formats. These sizes are ideal for many older vehicles, but I haven’t seen any circuit breakers sized for micro fuses or any of the other bitty fuse types found in today’s cars and trucks. That’s probably due to physical limitations for the circuit breaker mechanism. So if you mostly work on relatively new cars, don’t count on these gizmos to be much help.
Cost is a major difference between fuses and circuit breakers to consider. Blade or mini-blade fuses are pennies apiece. In contrast, a set of six blade circuit breakers will run you about $25, and that’s fairly consistent across different sizes and manufacturers. You could buy hundreds of blade fuses for that kind of money—and it’s always good to have plenty on hand. But I’ve come to the conclusion that these “circuit bladers” are the ultimate spare fuses. Here are three situations where they’d really come in handy.
Campers, hunters, van lifers, delivery drivers, Wyoming residents, and other adventuresome folk driving off the beaten path should absolutely toss a few of these breakers in their glove boxes before visiting desolate locations. Two is one, one is none, right? And one that can be reused over and over again could be very nice to have out in the bush.
Sure, most vehicles are equipped with a few spare fuses in their fuse boxes. Customers with a little DIY experience should be able to handle swapping in those spare fuses to limp their vehicles home when electrical trouble strikes. And if the fuse blows again, more spares can be found easily enough… unless customers like those mentioned above are traveling in sparsely populated areas where there are no towns, passing motorists or auto parts stores around to supply spares.
Big amps, big speakers, big wattage… You know exactly who these customers are. And popping fuses is a rite of passage, if not a way of life, for a lot of car audio enthusiasts, especially if they dabble in the DIY side of things. Circuit breakers might be a smart upgrade to keep these customers from getting frustrated while setting up or changing their audio systems.
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