Blade Fuse Chart
| Color | Rating | Note |
|---|---|---|
| Dark blue | 0.5 A | โ |
| Black | 1 A | โ |
| Grey | 2 A | โ |
| Violet | 3 A | โ |
| Pink | 4 A | โ |
| Tan | 5 A | โ |
| Brown | 7.5 A | โ |
| Red | 10 A | โ |
| Blue | 15 A | โ |
| Yellow | 20 A | โ |
| Clear | 25 A | โ |
| Green | 30 A | โ |
| Blue-green | 35 A | โ |
| Orange | 40 A | โ |
| Red | 50 A | Maxi only |
| Blue | 60 A | Maxi only |
| Amber/tan | 70 A | Maxi only |
| Clear | 80 A | Maxi only |
| Violet | 100 A | Maxi only |
| Purple | 120 A | Maxi only |
Size families (body L ร W ร H in mm, amps A)
| Family | Group names | Body (mm) | Amp range |
|---|---|---|---|
| Micro2 | APT, ATR | 9.1 ร 3.8 ร 15.3 | 5โ30 |
| Micro3 | ATL | 14.4 ร 4.2 ร 18.1 | 5โ15 |
| LP-Mini | APS, ATT | 10.9 ร 3.81 ร 8.73 | 2โ30 |
| Mini | APM, ATM | 10.9 ร 3.6 ร 16.3 | 2โ30 |
| Regular | APR, ATC, ATO, ATS | 19.1 ร 5.1 ร 18.5 | 0.5โ40 |
| Maxi | APX | 29.2 ร 8.5 ร 34.3 | 20โ120 |
Every blade fuse announces its rating in body color, and the chart is worth memorizing because the car never labels the socket: 10 A red, 15 A blue, 20 A yellow, 25 A clear, 30 A green cover most of what you will meet under a dash. Below 40 A the code is consistent across the size families - the same blue means 15 A whether it rides in a full-size ATO blade or a low-profile APS - which is what makes a glovebox fuse puller and a glance enough to service most circuits.
Above 40 A the code resets for the Maxi family only: 50 A red, 60 A blue, 70 A amber reuse the colors of the small-fuse ladder, and 25 A and 80 A are both clear. The saving grace is geometry: Maxi blades (29.2 x 8.5 mm) are physically too big for a regular slot, so the color collision cannot happen in practice - which is the working rule of the whole system, size family from the blade, then amp rating from the color. The six families in the second table differ in height and thickness (the two flat tabs are the constant), and the letter soup is simpler than it looks: ATO/ATC is the classic full-size blade, ATM its mini, APS the low-profile mini, ATR/ATL the micros - group names on the same dimensions are interchangeable.
How to use
- Identify the family by blade size before anything else: pull the fuse and match its body to the dimension table - a 19.1 x 5.1 mm body is regular (ATO/ATC), 10.9 x 3.6 mm is mini (ATM), 29.2 x 8.5 mm is Maxi. The family is fixed by the socket; only the amp rating is a choice.
- Read the rating from the color on the chart, then confirm against the number molded into the top of the blade - the two always agree on a genuine part, and the molded number survives fading that kills the dye.
- Replace like with like: same family, same amp rating. The color code is a label, the amp rating is the actual protection contract - and every legitimate substitution is downward-identical, never upward.
Frequently asked questions
Can I replace a blown 15 A fuse with a 20 A one?
No - and the color system exists precisely to make that hard. The fuse protects the wire, not the device: a circuit is built with copper sized for its load plus margin, and the fuse rating is the point where the wire needs a rescue. Swap blue for yellow and the next overload runs 33% more current through wiring that was never asked to carry it - the fuse holds, the insulation cooks, and the failure moves to a place with no fuse at all. Repeat offenders find out why the chart stops them: intermittent faults that blow fuses are a symptom (a chafed harness, a seizing motor, water in a connector), and upgrading the fuse deletes the only warning. Fix the cause, replace with the same color, and if the same fuse blows twice, stop swapping and start tracing.
What is the difference between ATO, ATC, APR and ATS fuses?
Mostly nothing that matters in a socket: they are group names for the full-size regular blade family - 19.1 x 5.1 mm, the shape nearly every car and fuse box standardized on from the 1970s onward. ATO and ATC are the classic two (ATO the original style, ATC the common successor with a different housing material), APR and ATS are later manufacturer designations on the same dimensions. A blade from any group fits any regular blade socket, and the amp rating is the only spec that changes behavior. The same pattern repeats down the size ladder: ATM/APM share the mini body, APS/ATT share the low-profile mini, ATR/APT share Micro2. That is why parts stores sell by family plus amps - the letters sort shelves, the color codes circuits.
Why do colors repeat above 40 A?
The Maxi family outgrew the small-fuse color list: 50 A red and 60 A blue reuse the colors of 10 A and 15 A, and both 25 A and 80 A are clear. Standards bodies kept the small-fuse chart intact (changing the color of every 10 A blade in every car was never viable) and gave the high-current family its own segment of the same ladder instead. In practice the collision cannot fire: a Maxi blade at 29.2 x 8.5 mm will not seat in a regular or mini slot, and vice versa, so the color only ever has to be unambiguous within one size family. It is also why the working procedure reads family first, then color: the blade geometry collapses the lookup to one column of the chart before the color does any work.
How do I find which fuse is blown without a tester?
Pull-and-look works more often than it should: a blade fuse has a window on top, and a spent element shows a visible gap or a dark smoky film, while a healthy one shows clean metal bridging the two tabs. Work in daylight or under a white flashlight - faded colors mislead, which is where the molded amp number on top beats the dye. When every fuse looks fine, the cheap upgrade is a test light or multimeter: with the circuit switched on, probe both small metal tabs on the fuse top - power on one side only means a blown fuse (the far side feeds the circuit), power on both sides means the fuse is good and the fault is downstream. Swapping a suspect fuse with an identical-colored neighbor of the same rating is the last resort check; just remember which is which when the symptom moves.