A number of components in the vehicle employ the use of relays to switch electrical signals to the parts and the following are some of them, the fuel injection systems,
Horns, starters and the fog lamps. A relay works on the principle of switching on and off of a low current path called the control circuit to switch on and off a high current path called the power circuit. Any malfunction or failure in the relay will mean that the pertinent component will also not function as it is supposed to. Generally, relays are affixed in the engine compartment and in the interior fuse and relay boxes.