Fuse

Cars have fuse boxes in the engine bay, under the dashboard and sometimes in the boot. Blade fuses carry their rating in amps on the top and are colour-coded. Large currents are protected by high-amp fuses or fusible links near the battery. A blown fuse is a symptom, not the cause. Replace it only with one of the same rating. If it blows again, there is a short circuit or overloaded component to find.

Cars use different fuse types, such as blade fuses in several sizes, cartridge fuses and large fusible links. The rated current is printed on the fuse and shown by its colour.

When current exceeds the rating, the link heats and melts within a fraction of a second, protecting the wiring from overheating. Fuse boxes are usually located in the engine bay, under the dashboard or in the boot. The cover or the owner’s manual shows which fuse protects which circuit.

Many power-supply codes and dead components are caused by a blown fuse. Never fit a larger fuse or bridge one: the wiring could overheat and catch fire. Always replace a fuse with one of the same rating. If a new fuse blows again, there is a short circuit or a faulty component that must be found; a larger fuse can cause a fire.