Fuses are components in the electrical system which are designed to go bad/blow out when the amperage gets too high along a circuit with a component that would be damaged by that level of amperage. Instead of replacing an expensive component, the fuse can be replaced at a much lower cost, and often more easily and/or faster.
Why Cars Have Fuses
In this Cars Simplified video, Steve answers the question "why do cars have fuses?" and covers some extra details you may become curious about along the way. This video was published July 27th, 2019.
Checking Fuses
No matter what fuse design you intend to replace, you should always replace a fuse with one of the same rating and size.
Standard automotive fuses, known as blade-type fuses, have a metal component in the middle which is just thick enough to handle anything below the amperage shown on the fuse. As long as this doesn't have a hole burned through it, it is a good fuse which can still be used.
German blade-type fuses (which are a solid color instead of a transparent color) have the metal component on the top instead of inside, so they can be checked while still plugged in. These can be replaced with another German blade-type fuse or a standard style blade-type fuse.
Glass tube style fuses have the metal element inside the tube. As with blade-type fuses, if that elelemt is burned out, it is bad and should be replaced.
- 2 Amp, Gray
- 3 Amp, Purple
- 5 Amp, Tan
- 7.5 Amp, Brown
- 10 Amp, Red
- 15 Amp, Blue
- 20 Amp, Yellow
- 25 Amp, Clear
- 30 Amp, Green
- 40 Amp, Orange
- 50 Amp, Red
- 60 Amp, Dark Blue
- 80 Amp, Clear
Amp Ratings
Fuses have a rating printed on them, stating at what amp level they blow out at, known as the breaking capacity. Ratings and the color typically associated with them are listed below, from lowest rating to highest:
These colors may differ by manufacturer and production date. Other amp ratings are available, but rare.
- Regular Blade-Type (ATO, ATC, ATS, APR, invented in 1976.)
- Mini Blade-Type (APM, ATM)
- LP Mini Blade-Type (APS)
- MAXI Blade-Type (APX)
- Micro2
- Micro3
- PAL Type
- JCase
- MCase
- ZCase
- Glass Tube
- Bosch Type
- Lucas Type
- Fusable Link
List of Automotive Fuse Types
Some manufacturers prefer using different types of fuses for certain applications, and often use a mix of types. The following list of automotive fuses covers most of what is available, but might not be complete.