One of the most approachable car maintenance tasks is replacing a blown fuse. In fact, most automakers place fuse boxes in easy-to-reach places because they anticipate their customers will want to replace them DIY. Here’s a step-by-step breakdown of how to spot a blown fuse and how to change it.
What Do Car Fuses Do?
Car fuses protect a vehicle’s electrical system by “blowing” if a short circuit creates too much current. If not stopped immediately, short circuits can cause damage to a vehicle, including a fire.
When Should I Check the Fuses?
Fuses are the main safety feature of your vehicle’s electrical system. It could be a blown fuse if your headlights suddenly stop working or the stereo doesn’t turn on. In short, it’s time to check the fuses to see if it’s electronically controlled and not functioning correctly.
How to Check Car Fuses
Your owner’s manual will tell you which fuse goes with which system. With your car turned off, open the fuse box and visually check the fuse for the system that’s malfunctioning. A blown fuse will be visually obvious.
When removing a fuse to check it, don’t use metal pliers. Fuses are delicate and most fuse boxes will have a set plastic pliers stored inside for that purpose.
Why Do Fuses Fail?
Fuses usually fail for two reasons:
- The fuse is old.
- There’s a short circuit.
A short circuit can be caused by several issues, including:
- Faulty car part
- Damaged wiring
- Water leak
Why Should I Replace a Fuse Myself?
Cost! Taking a car in for service not only costs money, but it takes time. Replacing a fuse should only take a few minutes.
How to Replace a Blown Fuse
Step 1: Locate the fuse box
The fuse box is a small plastic box with a plastic cover. Sometimes they’re located under the hood in the engine bay. Another common location is in the cabin beneath the steering wheel. In less-common cases, you’ll find the fuse box in the glove box, under the glove box, or in the trunk. Refer to your owner’s manual for the precise location.
The manual and the inside of the fuse box cover) should have a diagram that maps out the location of the various fuses, which will be important later. The fuse box should also have a fuse puller.
Step 2: Check for blown fuses
Turn the car off. Check the owner’s manual or fuse box cover to see which fuse corresponds to the malfunctioning system. The easiest way to check a fuse is to pull the fuse you suspect is blown and check it visually.
Fuses are delicate! Unless you have steady hands and have been doing this for some time, using a set of pliers to pull the fuse is unwise. Use the plastic fuse pullers in the box (shown above) to remove the fuse.
What does a blown fuse look like?
If a fuse is blown, you should be able to see that the wire in the middle has melted.
Multimeter or Test Light
Another way to check a fuse is to use a multimeter or a test light, available at most auto-parts stores. Some national chains will even let you borrow one to check a fuse box in their parking lot quickly. The benefit of this method is that you don’t need to pull the fuse to check whether it has blown.
Step 3: Install the new fuse
Make sure you replace the blown fuse with an identical fuse (same number and size). There are usually a few spare fuses in the fuse box, but if not, you’ll have no trouble buying one at a gas station or auto parts store.
Once installed, test the fuse by turning the car on and checking the previously malfunctioning equipment. If that equipment is malfunctioning, double-check that you have the correct fuse.
Please take a picture of the blown fuse and note when it blew, what it controls, and how many times it has blown. You can keep those notes on your phone or write down in the owner’s manual. A 15-year-old car might have dozens of fuses, and a newer car may have many more. These notes can help your mechanic diagnose any long-term issues.
Step 4: Keep an eye on the issue
If you keep blowing that particular fuse, you may have a larger issue on your hands. For a larger issue, you’ll likely have to go to a mechanic. In that case, the blown fuse is a symptom of the real problem, not the problem itself.
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