Step 1: Locate the fuse
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.
Never replace a blown fuse with a higher-amp fuse. Always replace the fuse with one with the specified amp rating. You may install the next-smaller-rated fuse to get you by in a pinch until you can purchase a replacement.
Step 2: Test for the bad fuse
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).
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
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.
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.