Several electrical accessories in the vehicle, including the fuel injection system,
Horns, starter, and fog lamps, utilize relays to transmit electrical signals to the components. Relays operate by using a low-current circuit, known as the control circuit, to open and close a high-current circuit, referred to as the power circuit. A defective relay will result in improper operation of the associated component. Typically, relays are mounted in the engine compartment and in interior fuse and relay boxes.