How to test and replace a blown car fuse without guessing the amperage
A beginner-safe guide to finding the right fuse panel, spotting a broken metal strip, matching amp ratings exactly, and comparing a $1-$10 DIY budget with $20-$50 shop labor examples.
The short version
When one electrical thing on your car suddenly dies—radio, power windows, a cigarette-lighter outlet, or the wipers—the first check is often a fuse. A fuse is a small plastic part with a thin metal strip inside. That strip melts on purpose when a circuit draws too much current, so the wiring and the expensive device behind it do not burn.
Family Handyman puts a straightforward fuse job at about five minutes, roughly $1 for one fuse, and a total project cost of less than $20. An assortment pack runs about $10, and the same source lists $20–$50 for professional labor when a shop handles a fuse-related wiper fix. 12
The non-negotiable rule: match the amperage printed on the old fuse. Guessing a higher number can turn a cheap protector into a fire risk. Car and Driver makes the same point: the wrong amp rating can cause serious electrical problems. 3
What a fuse does—and when to stop
Amperage (written as A on the fuse) is how much current the fuse will allow before it opens the circuit. Modern cars mostly use blade fuses—flat plastic bodies that push into a panel. Family Handyman groups common sizes as mini, standard, and maxi. Mini and standard protect everyday circuits such as lights and radios. Maxi fuses protect high-draw systems such as anti-lock brakes, a rear defogger, or traction control. 1
Blade fuses are also color-coded. Family Handyman's examples: blue = 15 A, yellow = 20 A, green = 30 A. Always read the number on the fuse and on the panel diagram; color is a helper, not a substitute for the printed rating. 1
Use this guide when:
- One accessory or lamp circuit stopped working.
- Your owner's manual shows a replaceable blade fuse for that circuit.
- You can open the panel without cutting wires or removing major trim you have never taken off.
- The fuse panel cover or manual lists the amp rating for that slot.
Stop and get a diagnosis—or at least a vehicle-specific procedure—when:
- The new fuse blows right away or soon after you replace it. Family Handyman and Car and Driver both treat that as a sign of a short or another circuit fault, not a fuse shopping problem. 13
- Several unrelated systems failed at once.
- You smell burning plastic, see melted connectors, or find water in the panel.
- The failed part is a large under-hood maxi fuse, a battery junction block, or a fusible link (a special fused wire, not a push-in blade fuse) and you have not done that job before.
- The car has no power at all after a crash or major electrical event.
A blown fuse is the symptom. The fuse did its job. Installing a larger fuse does not fix the underlying overload.
Tools and materials
| Item | Why you need it | Planning cost |
|---|---|---|
| Correct replacement fuse (same amp, same blade size) | Restores the circuit without oversizing protection | About $1 each; ~$10 for a mixed assortment 12 |
| Fuse puller | Pulls tight mini fuses without crushing them | Often clipped inside the panel cover; a few dollars if missing 1 |
| Flashlight or phone light | Lets you read the diagram and see the metal strip | Usually already owned |
| Owner's manual | Shows panel locations and which fuse feeds which circuit | Already owned |
| Optional: needle-nose pliers | Backup puller for larger blade fuses if used gently | $5–$15 if you do not own a pair |
| Optional: spare fuse kit for the glove box | Covers common amps on the road | About $10 for a large assortment 2 |
Many panel covers already hold a few spares and a plastic puller. Family Handyman reminds you to restock those spares after you use them. 1
Step-by-step: test and replace a blade fuse
- Turn the ignition off. Family Handyman starts here so you are not probing a live accessory while you pull parts. 1
- Find every fuse panel your car uses. Check the owner's manual. Common places include under the dash, behind a side kick panel, under a rear seat, and under the hood in a black plastic box. Cars often have more than one panel. 1
- Match amp rating, color, and physical size. Read the number on the old fuse and the diagram. Buy or install a fuse with the identical amperage and the same blade body (mini, standard, or maxi). Color should match the chart when the number does. 1
- Seat the new fuse firmly. Push it straight into the empty slot until it sits level with its neighbors. Do not force a fuse that does not fit the slot shape.
- Test the circuit. Turn the ignition on and operate the device that failed. If it works, put the cover back on and restock any spare you used. 1
Roadside stopgap only
Car and Driver describes a temporary move for a jam: move a working fuse of the same amperage from a less critical circuit (for example, a rear wiper when rain is not expected) into the more important slot. Treat that as a short trip home, then buy the correct spare. Never "borrow" a higher-amp fuse for the dead circuit. 3
Family Handyman allows the next-smaller amp rating only as a temporary get-you-home substitute until you buy the correct fuse. It still forbids anything larger than the specified rating. 1
Common beginner mistakes
| Mistake | What goes wrong | Better habit |
|---|---|---|
| Installing a higher-amp fuse | The fuse no longer opens at the designed limit; wiring can overheat | Match the printed amp rating exactly 13 |
| Buying by color alone | Color charts can vary by fuse family; the wrong body size will not seat | Match number, color, and mini/standard/maxi body |
| Skipping the visual check | You replace a good fuse and miss the real fault | Hold the fuse to light and look for a continuous metal strip 1 |
| Pulling the wrong slot | A working circuit goes open while the dead one stays dead | Use the cover diagram and the owner's manual first |
| Crushing a mini fuse with pliers | Plastic cracks and pieces stay in the panel | Prefer the plastic puller; pull straight out |
| Leaving the cover off | Dirt and moisture reach the terminals | Snap the cover on after the test |
| Stacking new fuses into a circuit that keeps blowing | You spend money while the short remains | One replacement; if it fails again, diagnose the circuit 1 |
| Treating a fusible link like a blade fuse | The repair needs the correct fused wire and a proper splice | Stop and use a vehicle-specific fusible-link procedure |
What can you save?
Family Handyman frames a DIY fuse check as roughly $1 and about five minutes, with a full project budget under $20. For a related wiper-fuse situation, the same publisher lists about $10 for a 100-piece assortment and $20–$50 in professional labor. 12
Use this math:
Your saving = the shop's quoted labor (and parts markup) − what you spend on the correct fuse.
Worked examples from those Family Handyman figures—not a national shop average:
| Your DIY purchase | Shop labor example from Family Handyman | Difference |
|---|---|---|
| $1 single fuse | $20 labor | About $19 saved |
| $10 assortment kit | $35 labor midpoint of the $20–$50 band | About $25 saved on this visit, plus spares for later |
| $1 fuse you already owned in the glove box | $50 labor at the top of the band | About $49 saved |
If the quote includes full electrical diagnosis, wiring repair, or a module, it is a different job. Compare only the portion that covers finding and replacing the fuse itself.
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DIY makes sense when one labeled circuit is dead, the panel is accessible, and you can match the amp rating. If the replacement fuse fails again, the money-saving move is diagnosis, not a larger fuse.
Tutorials worth watching
ChrisFix does not publish a standalone walkthrough for ordinary blade-fuse replacement. Use these verified alternatives for the job in this issue, then turn to ChrisFix when the problem is a fusible link or a short that keeps killing power.
- 1A Auto: How to Find and Replace A Blown Fuse in Your Car or Truck — a short, universal find-and-replace demo for blade fuses. 4
- AutoZone: Changing a Fuse — a two-minute parts-counter style walkthrough of the same basic steps. 5
- Cars Simplified: Your Car's Fuse Box Explained — useful background on fuse boxes, relays, and why empty slots sometimes exist on purpose. 6
- ChrisFix: How to Replace a Fusible Link (Car won't Start) — related electrical protection, not a blade fuse. Watch this only when the failed part is a fusible-link wire rather than a panel fuse. 7
- ChrisFix: How to Find a Short in your Car — the next step if fuses keep blowing or the battery dies overnight from a parasitic draw. 8
Watch the 1A Auto walkthrough before you pull the first fuse:
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Next week: we'll jump-start a car with cables the safe way—clamp order, what not to touch, and when a jump will not fix a deeper problem.
References
- 1Family Handyman: How to Check and Replace Car Fuses
familyhandyman.com
- 2Family Handyman: Why Won't My Windshield Wipers Work?
familyhandyman.com
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