The headlight indicator switch stalk is attached to the steering column. This stalk has levers on it that are used by the driver to operate the headlights or indicators of the vehicle and is wired in to the power supply unit of the vehicle using a multi-connector plug. The headlights and indicator are powered by a 12-volt electrical system known as a closed circuit loop system. This means that electricity is not flowing to the headlights or indicators when they are switched off. When the driver uses the levers on the headlight indicator switch stalk the current is passed from the power supply to the headlights or indicators, opening the circuit loop. Once a vehicle has finished turning it’s common for the indicators to turn themselves off using a function that’s built in to the headlight indicator switch stalk.
It’s rare that a headlight indicator switch stalk will become damaged through wear and tear, but they can fail to self-cancel when indicating to turn. Other issues that may arise are the damage to wires which can cause burn outs or reliability issues. Faulty stalks should be replaced immediately and damaged wiring replaced.