Why Is My Car’s Turn Signal Blinking Fast?

While you’re probably used to the “click, click, click” sound of your car’s blinker, there are certain times when it can “click” faster than normal. Fortunately, a fast-clicking blinker is somewhat of a common issue. Here are some possible causes and what you can do about them.

How does a turn signal work?

A rear driver's side view of a blue 2022 Volkswagen Taos SUV's taillight and back window
2022 Volkswagen Taos | Volkswagen of America, Inc.

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According to Napa, your car’s turn signal is operated when power from the battery runs through a fuse and to the turn signal relay. When you click your car’s turn signal “left” or “right,” it completes the circuit and it activates and sends power through the secondary load circuit. That secondary load circuit includes a flasher and the bulbs that light up when you pick the direction that you desire.

The flasher that is connected to the bulbs contains a small strip of metal that bends and straightens when it’s heated or cooled. This reshaping of the strip is what completes or breaks the circuit to the bulbs. Considering the strip of metal for the flashers is so susceptible to temperature changes, you can see how it needs to bend at exact intervals and under the correct electrical conditions.

Now that we understand how important completing the circuit to the flasher and bulb is, we can start to see how the different components in the current can attribute to a fast-blinking turn signal. Here are some of the most common causes:

  • Bad bulb: The lights on your car can burn out after years of use. A bad bulb will alter the resistance in the circuit, which will in turn send a different current through the blinker. Test the lights by activating the signal and seeing if they light up. If not, then inspect the actual bulb and replace it if it looks darkened or black.
  • Aftermarket lights: Although some aftermarket lights look cool, they don’t always match up to your car’s electrical system. If your fast blinker is due to an aftermarket light – such as LED lighting – then remove it and see if the issue still persists.
  • Bad connection: Since your car’s blinker system is connected by wires, it is possible that at least one of the wires in the system is corroded or worn out. Relays and flashers can go bad over time as well. In this case, you can trace the wires in the system, the relay, and the flasher and inspect them to see if any one of those components is the culprit.

Is a fast-blinking turn signal illegal?

Yes. According to Horsepowerful, the Department of Transportation requires that vehicles’ turn signals flash at a maximum of 120 flashes per minute. So if your turn signal is flashing faster than that and you get pulled over, you could technically be cited for being in violation of the law.

We would be surprised if you received anything more than a “fix it” ticket for such an issue. But be sure to check your state and local laws to find out. Also, remember to do a quick check on your car’s light every month or so to make sure that they’re not burnt out.