All indicators on a vehicle are designed to let other road users know that a vehicle is about to make a turn or change lanes. The front and rear indicators are both used in tandem as the hazard warning lights system which informs other road users of a potential hazard ahead.

The white indicator is situated on the exterior lights panel, towards the extreme corner of the vehicle. The indicator bulb is protected by a plastic cover or lens. When the indicator is operated the indicator light will flash regularly until it is switched off. This will be clearly visible to vehicles immediately behind. The indicator stalk is to be found on the steering column along with other light switches and wiper controls. The indicators can either be switched off manually by the driver or they may switch off automatically if the vehicle has an auto-return mechanism fitted. This is activated once the steering wheel returns to its straight-ahead position. The amber colour of all indicators is achieved by an amber-coated bulb behind the white or clear lens.

The most common fault with indicators is due to the bulb having blown or that faulty contacts with the bulb-holder are stopping the power from the battery reaching the bulb.