Vilkkukytkins

Vilkku means blink or flash in Finnish. Kytkin means switch. Therefore, a vilkkukytkin is a flasher relay, also known as an indicator relay or turn signal relay. This electronic component is crucial for the operation of a vehicle's turn signals or hazard lights.

The primary function of a vilkkukytkin is to control the intermittent blinking of the turn signal lights. When the driver activates a turn signal, current flows through the vilkkukytkin. The relay then interrupts and re-establishes the flow of electricity to the indicator bulbs at regular intervals, causing them to flash on and off. This blinking action alerts other road users to the vehicle's intended direction change.

Modern vilkkukytkimet are typically electronic, offering greater reliability and consistency compared to older thermal or mechanical types. Electronic relays can also incorporate additional features, such as audible alerts or the ability to detect a burnt-out bulb and adjust the blinking speed accordingly. In some vehicles, the vilkkukytkin is integrated into a larger control module, often referred to as a body control module (BCM) or electronic control unit (ECU).

The characteristic clicking sound often associated with turn signals is usually generated by the vilkkukytkin itself, though in some electronic systems this sound is simulated through a separate speaker. Failure of the vilkkukytkin will result in the turn signals either not blinking at all, or remaining constantly illuminated.