Fuses & Circuit Breakers

Electrical System

Description

Older vehicles use cartridge type fuses that have a fuse element encased in a glass cylinder. The fuse capacity is marked on the end conductors of this type of fuse. The blade style fuse has become almost the universal standard for fuse applications today. The blade style fuse makes it much easier to visually determine whether a fuse is blown or not.

There are three different types of blade fuses: the mini fuse (used in small-current applications), the standard auto fuse (used for most common circuits), and the maxi fuse (used for higher-current applications and in some case to replace a fusible link).

When a fuse "blows", it must be replaced. Carmakers use circuit breakers --a resettable rather than replaceable circuit protector -- instead of fuses in circuits such as the headlights, power seats, power windows, and others.

Purpose

Fuses and circuit breakers are designed to protect circuits in the event of electrical overload.

Maintenance Tips/Suggestions

Today's electrical systems have more than one fuse panel that can be found in different locations throughout the vehicle. Blown fuses or a tripped circuit breaker usually indicate more serious electrical circuit problems such as a short circuit or an electrical consumer that is using more current than the circuit is designed for. Electrical systems can be quite complex, and as such should be serviced by a professional technician.