At its core, an Automotive relay is an electrically operated switch. The term "12V" refers to the typical operating voltage of vehicles, which is standardized for most modern cars and trucks. A 12V relay works by utilizing a low-voltage current, often generated from the car's battery, to control the flow of current to higher-power circuits that control various automotive functions.

    Relays are composed of a few essential parts： a coil, contacts, and a spring mechanism. When current flows through the coil, it creates a magnetic field that attracts a movable armature. This action opens or closes the contacts, thereby completing or breaking the circuit to the device being controlled. Once the current is cut off, the spring mechanism ensures that the armature returns to its original position, opening or closing the circuit as necessary.