An automotive relay is an electromechanical switch that uses a small electrical signal to control the operation of a larger electrical current. Relays are typically used to control high-power components, such as lights, horns, or fuel pumps, with a low-power signal. The basic operation of a relay involves an electromagnetic coil that, when energized, pulls a contact to complete a circuit, allowing current to flow to the desired component. When the coil is de-energized, the contact returns to its default state, cutting off the current.

    In vehicles, relays are often used for functions such as activating headlights, controlling air conditioning systems, or even managing engine functions. They are essential for ensuring that electrical components function properly while preventing damage to sensitive circuits.