Everyone who has been in a car knows the distinctive sound of turn signals. That sound is the result of heat bending a small piece of metal back and forth. Inside the turn signal flasher is an electrical connection that is not connected when the turn signal is not being used. One side of the connection is the turn signal bulb and the other is electrical power.
When a turn signal is switched on, electricity is sent through a wire wrapped around a small piece of steel. The electricity heats up the metal which bends and expands, linking the electrical connection and illuminating the turn bulb. Since the power is going through the connection and not the wrapped wire, the metal cools down again and bends back, disconnecting the power and switching off the turn signal bulb. This cycle is repeated each time you use your turn signal and constantly heats and cools the steel connection strip.
These days, auto manufacturers use computers to control turn signals instead of mechanical flasher units that can fail over time. Even these modern cars still use traditional sounding clickers and indicator lights on your dashboard to indicate when your turn signal is active.
What the direction indicator lights mean
The left and right flashing arrows on your dashboard are only used to show when the turn signal is active. When you switch on your hazard lights, both the turn signal arrows will flash. When the indicator flashes quicker than normal, check all of the bulbs as one has likely burnt out. The quicker flashing is caused by a change in the overall resistance in the circuit when one of the bulbs goes out. Switch out the bulb and everything should return to normal. If the bulbs haven’t burned out and the turn signal arrows are still flashing, have the rest of the circuit inspected, namely the relay and turn signal flasher.
Is it safe to drive with the direction indicator lights on?
You should always use your turn signals when driving. They inform everyone around you of your intended driving actions so they aren’t surprised if you start to merge into their lane. Always make sure that you turn off your turn signals if the steering wheel doesn’t automatically do it for you. Change out any bulbs that burn out so your turn signals stay in good working order.
If your turn signals aren’t working properly, our certified technicians are always available to assist you in diagnosing any problems.
This article originally appeared on YourMechanic.com as What Do the Direction Indicator Warning Lights Mean? and was authored by Spencer Cates.