Skip the auto shop - Our mechanics make house calls

How a Car Turn Signal Works

turn signal

A requirement for all automakers is to equip each vehicle with proper, standard lighting. Every vehicle is equipped with several lighting systems including:

  • Headlights
  • Taillights and brake lights
  • Corner marker lights
  • Hazard or warning lights
  • Turn signal lights

Turn signal lights are important for the safe operation of your vehicle. They indicate your intentions to change lanes, turn a corner, or pull over to the roadside. While not everyone uses their turn signals as regularly as they should, their usage dramatically reduces the number of accidents and driver errors.

How Car Turn Signals Work

Turn signals require electrical power in order to illuminate the turn signal light bulbs. The circuit is protected by a fuse in the power junction block in case of an electrical fault. When the turn signal lever is activated in either direction, a circuit is completed that allows power to flow to the front and rear turn signal lights on the selected side.

When the signal lights are turned on, they are not illuminated constantly. They flash in a rhythmic pattern to draw the attention of other motorists and indicate your intention. This is achieved by routing the power to the turn signals through a flasher or module that sends pulses of power to the lights instead of a steady stream.

When you complete your turn and turn the steering wheel back to center, a cam on the steering column catches on the turn signal lever and cancels the turn signal operation. If the cancel cam on your steering column is broken or you only take a slight turn, the signals may not cancel on their own and you will need to turn the signals off by moving the signal lever on your own. Make sure to get your turn signal fixed as soon as possible.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...

Related questions

Q: How do I use the lane change signals?

You should always use your signals when you are changing lanes, to alert drivers around you that you are doing so. You can signal a lane change with the turn signal lever, which is located on the left side of...

Q: Car has electrical problems and starting issues

My guess is that the problem is with the body control module (BCM). The BCM functions as the power mode master (PMM). In this role, it receives an input from the ignition switch when the key is turned to the...

Q: Turn signal malfunctioning, as well as other lights

The front control module controls all of the vehicle's lighting functions. From your description it sounds like this module is failing. However, before replacing the front control module, connectors and wiring should be checked to ensure there is no harness...