The Importance of Fuses and Relays

The electrical system of a modern car is very complex. This is because cars have a large number of power consumers that need to be supplied with electricity. The sources of electricity for a vehicle with an internal combustion engine are the battery (when the engine is not running) and the alternator (when the engine is running).

There are hundreds of consumers of electricity, such as controllers (e.g. an on-board computer or an ABS unit), sensors (from sensors that monitor the air supply to the engine to sensors that check whether windows or doors are closed), electric motors (e.g. a fan, wipers, power seats), light sources, and many others.

The large number of wires and consumers means that damage to the electrical system (e.g. wire chafing, short-circuiting) is not difficult, especially when the car is exposed to a number of factors such as vibration, corrosion and the possibility of burning out the wires due to contact with a hot engine.

Fuses and relays protect users from short circuits or overloads.

What could happen if there were no fuses in cars?

Units that use electricity could fail (overheat). A short circuit could also cause a fire that could burn the whole car. In the event of a short circuit or overload, the fuse burns out and cuts off the electricity supply to the unit in question or (usually) to a group of units. A single fuse can be responsible for several systems, for example, it can protect the central locking system and the interior lighting of the car.

A blown fuse or relay can also indicate a serious problem – a short circuit in a particular electrical circuit. It is also possible that a new fuse may also burn out quite quickly. In this case, it is necessary to determine the cause of the fault. An auto electrician must check all the units protected by the fuse in question, one by one.

Easy Fuse box and Relay Identification

That’s where we, WhichFuse.com, come in, to make it easier for both the average car driver and the experienced auto electrician to identify which unit is responsible for a blown fuse. Here you will find diagrams of fuse boxes and relays for many different car models. We will show you where the fuses and relays are located in the car’s interior, in the trunk or under the bonnet.