Replacing Auto Fuses

Step 1: Locate the fuse

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Photo 1: Under the hood

Check your owner's manual for the location of your fuse box. It's often under the hood.

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Under the dash

Some types of cars locate the fuse box under the dash, beneath the side kick panels or under the rear seat.

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Photo 2: Fuse diagram shows fuse locations

Remove the cover and look for a locator sticker. You may need to check your owner's manual for the location of the fuse you're looking for.

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Back side of cover

Many fuse covers contain extra fuses and fuse pullers on the back side. If you use one of them, replace it the next time you go to the auto parts store.

Vehicles today have 40 or more fuses grouped in two or more places. Usually located in or around the instrument panel near the dash, fuses can also be found under the hood and even under the rear seat.

Next time your radio, lights or other device stops working, chances are a blown fuse is the culprit. Look under “Fuses” in your owner's manual for help finding your fuse panels. Most manuals have a diagram showing you where each fuse box is. Each fuse panel cover should have a diagram listing each device and the corresponding fuse.

Step 2: Test for the bad fuse

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Photo 3: Test with an automotive light

Clamp the grounding lead of your test light to a metal component. Turn the ignition key to the “run” position. Then probe both of the tiny test ports in the face of each fuse. The light should illuminate at each port. If it doesn’t, the fuse is blown.

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Photo 4: Test with a fuse tester

Turn the key to the “run” position and press the tester prongs into the test ports. The LED will light up if the fuse is good.

Once you find the fuse box, locate the right fuse by checking the diagram located inside the cover. Then test it with a standard automotive test light (photo 1). Or, buy a fuse testing tool (about $5) at an auto parts store and just touch it to each fuse in turn (photo 2).

Three common fuse sizes

Not All Fuses Are Alike

There are at least seven different styles, so you'll need the blown fuse to match it up with the right replacement. Here are the three most common sizes.

Step 3: Replace the fuse

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Photo 5: Pull the fuse

Remove the fuse that's labeled for the device that's not working, for example, the fan, radio, lighter or marker lights. Use a needle-nose pliers or a fuse puller (available at auto parts stores).

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Photo 6: Burned fuse

Hold the fuse up to the light to see if it's burned out. You'll see a fine wire connecting the two sides if the fuse is good. If a section of that wire has burned away, the fuse is bad.

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Good fuse

In a good fuse, the wire between the two sides is still whole.

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Photo 7: Types of fuses

Most fuses used in vehicles today are one of three types: mini, standard or maxi. The mini and standard are fast-acting fuses that protect the majority of your vehicle's circuits, including those for lights and radios. The maxi fuses are slow-acting fuses that protect circuits with a large current draw such as those for anti-lock brakes, rear window defogger and traction control.

Fuses are color coded by amp rating. For example, a standard blue fuse has a 15-amp rating, yellow is 20 amps and green is 30. Before you buy fuses, keep in mind that the fuse panel cover often contains spare fuses and even a fuse puller. Just be sure to replace the spares so they'll be there the next time you need them. You can buy them at any auto parts store and at well-stocked service stations.

Note: If your new fuse blows soon after installing it, you could have problems in that circuit. Schedule an appointment with your service station or dealer for an expert diagnosis to repair the problem.

In-line fuses

In-Line Fuses

Some accessories that aren't factory installed may have a remote in-line fuse. These fuses can be located under the dash, under the hood or even in the trunk depending on the circuit they protect. They most likely protect an aftermarket accessory like fog lights or a CD changer. The best way to find an in-line fuse is to trace the wire from the accessory to the fuse panel. Along the way, you'll notice a fuse container that looks like one of these shown. Open the housing to pull out the fuse and examine it. Replace it with one of the same size and amperage and snap the housing back together.