How Do Car Turning Lights Work?

Car turning signals operate via a signal switch.

Turning signals refer to signal lights positioned near the front and rear corners of a vehicle on the right and left sides. Turning signals, when used properly, indicate to other drivers in the vicinity that the driver is preparing to change vehicle direction.

Signal Stalk

Turn signals activate via a horizontal lever, commonly referred to as a stalk, that extends from the steering column or mounts to the dashboard. The operator pushes the stalk anticlockwise to activate a left turn signal or clockwise for a right signal. The stalk also automatically moves in the same direction as the steering wheel during a turn and deactivates the signal based on the opposite motion of the wheel.

Signal Switch

The light bulbs, called blinker bulbs, blink or flash via the stalk, connecting to a turn signal switch. The turn signal switch breaks and reconnects the circuit in the blinker bulb by opening or closing contacts that either allow or prevent current from flowing through the circuit.

Regulations

Turn signals must flash or blink at a per-minute rate of between 60 and 120 blinks. International regulations require all turn signals to activate at the same time, or all right or left turn signals located at the front and rear of the vehicle must flash simultaneously.

References

• 2 Car Pros: How Turn Signal Work
• "Car Science"; Richard Hammond; 2008

Resources

• "How to Repair Your Car"; Paul Brand; 2006