There are several electrical accessories that are fitted on the vehicle; the fuel injection,
Horns, starter and the fog lamps all use relays to switch on or off as well as switch the electrical signal to the relevant components. It is a combination of a control circuit, which is a low current path and a power circuit which is a high current path. A faulty relay will lead to the wrong functioning of the linked element. Commonly used place of mounting of relays is the engine compartment area and interior fuse or relay compartments.