Home Tips & Tricks How Does a Turn Signal Flasher Work?

How Does a Turn Signal Flasher Work?


Hand signals are the norm for drivers using a vehicle that is not equipped with turn signals. Automatic turn signals have pretty much eliminated this practice, save for some motorcycles and antique autos. A simple electrical device flashes the turn signal lamps on and off, eliminating the need to stick your hands out the window to signal other drivers your intended direction. Activating the turn signal lever or the hazard light switch of your vehicle activates the flasher and causes the needed lamps to flash on and off, signaling other drivers where you intend to go.

Flasher Operation

A turn signal or hazard light flasher relies on current from the vehicle battery. The flasher gets the needed current when the turn signal or hazard light switch is activated. As is, this current is insufficient to light the signal lamps because of a resistor within the flasher. Once a bi-metal wire within the flasher unit heats up from the battery current,…