Modern trucks and cars use several fuse styles, often in the same fuse box. Before you buy a replacement, identify the style and the amperage printed on top.
Blade fuses
Blade fuses have two flat metal prongs and a colored plastic body. They come in several sizes:
- Standard (ATO/ATC): the original full-size blade fuse.
- Mini (ATM): smaller, very common in newer vehicles.
- Low-profile mini: same footprint as a mini, but shorter, so it sits nearly flush.
- Micro2 and Micro3: compact fuses in the newest fuse boxes. Micro3 has three prongs and protects two circuits.
- Maxi: large blade fuses for high-current circuits.
Common blade fuse colors (standard and mini):
| Amps | Color |
|---|---|
| 5 | Tan |
| 7.5 | Brown |
| 10 | Red |
| 15 | Blue |
| 20 | Yellow |
| 25 | Clear / natural |
| 30 | Green |
Always go by the number printed on the fuse, not the color alone.
J-case fuses
J-case fuses are box-shaped cartridge fuses with female terminals that push down onto pins in the fuse box. They protect higher-current circuits, typically 20 to 60 amps, and come in two heights: standard (tall) and low profile. Match the height of the original, or the fuse box lid may not close.
J-case fuses use their own color code:
| Amps | Color |
|---|---|
| 20 | Blue |
| 25 | White / natural |
| 30 | Pink |
| 40 | Green |
| 50 | Red |
| 60 | Yellow |
M-case fuses
M-case fuses are a smaller version of the box-shaped cartridge fuse, used where space is tight. They are not interchangeable with J-case fuses.
Replacing a blown fuse safely
- Turn the ignition off.
- Find the fuse using the diagram on the fuse box lid or in the owner's manual.
- Pull it with the fuse puller and look for a broken element.
- Replace it with the same style and the same amperage.
Common questions
Can I use a J-case fuse instead of an M-case?
No. They are different sizes and are not interchangeable. Replace like with like.
Can I use a low-profile mini fuse in place of a regular mini?
They share the same footprint and ratings, so they usually fit, but a low-profile fuse sits lower and can be harder to pull. Use the style your fuse box was designed for when possible.