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Why Do Signal Lights Blink Faster Sometimes?

Turn signal, blinker, indicator light; Whatever you call them, they are the only communication you have to drivers around you. Your turn signal tells other drivers what direction you’re planning to go and yield to your next move. 

According to SAE Standard J590b, functioning turn signals have an average cadence of 60 and 120 blinks per minute. When something is not right, the speed of the blink or the sound of the click can increase. But what causes this increase? 

Read on to find out the answer to your most burning question, “why is my turn signal blinking fast?”. 

How Your Turn Signals Work

The turn signal circuit is pretty standard within most vehicles. 

Part 1: The Signal Circuit

Power for the signal runs through a fuse from the battery to the turn signal relay. The control circuit completes when you move the signal arm up or down to activate your right or left signal.

turning on blinker inside of car

Part 2: Bulb

It then activates and sends power through a second load circuit that includes the bulbs to correspon

d to your chosen direction. The bulb is then activated. Instead of a solid “on” state, the power is sent through a flasher to create the flashing motion.

 Part 3: Flashers

Flashers are temperature-controlled and designed to bend at precise intervals based on electrical conditions. Flashers are engineered with a small band of metal that is heat resistant. The current that flows through the band causes the metal to heat and cool by straightening and bending to break or complete the circuit to create the flashing motion.

Why Your Turn Signal is Blinking Fast

The circuit’s current is dependent on the load demand, also known as bulbs. The circuit has defined calculations for its current, resistance, and voltage. A change in any of these elements can alter the timing of the blinker. 

Common causes for fast blinking include:

A Failing or Failed Bulb

A failed bulb is the most common cause of a vehicle’s turn signal

 blinking fast. A failed bulb interrupts the resistance in the circuit, sending an altered current through the signal. 

To determine whether your bulbs have failed, test each signal direction to see if any bulbs are out. You can also inspect each bulb to check for broken filaments, darkness, or cloudiness on the glass portion of the bulb. 

Poor Ground Connection or Inadequate Voltage

Combination switches that are dirty or need cleaning are good indicators that the connections are in disrepair. Similarly, bad combination switches can be the res

ult of poor voltage. 

If there is a lack of voltage in the car, the indicator is likely to blink fast.

Damaged Connections

Corroded, fried, worn through the insulation, or loose connections will alter the resistance and blinking speed. 

Relays and flashers can wear out over time or succumb to water damage, extreme temperatures, or other environmental conditions.

turn signal on truck side mirror

How To Fix a Fast-Blinking Turn Signal

In older vehicles, replacing a bulb, relay, or fuse might have been a simple task. These days, modern cars have many nuances that can make an otherwise simple task rather tricky. 

Taking your vehicle to a trusted automotive technician will likely save you some time and some grief, especially if your car is experiencing an underlying electrical problem. 

To resolve your vehicle’s fast-blinking turn signal issue:

  • Check all wiring for damages
  • Clean turn signal components and surrounding areas
  • Change fuses
  • Test or replace the vehicle’s battery
  • Replace bulbs

How To Replace a Turn Signal Bulb

Replacing a turn signal bulb in most cars is relatively easy. However, if you don’t feel comfortable replacing the bulb yourself, take your vehicle to a trusted automotive technician to complete the service for you. 

Remember to avoid touching the glass area of the new light bulb with your bare hands to avoid damaging the unit. Depending on your vehicle’s design, you may need to unscrew the mounting screws to remove the turn signal housing before beginning the replacement steps.

  1. Remove the old turn signal bulb by opening the hood and locating the unit requiring replacement.
  2. Remove the electrical connecter by pushing the locking tab down and back.
  3. Remove the worn-out bulb by turning the socket counterclockwise. Depending on your vehicle, you may need to pull the bulb straight out or push the bulb inwards while turning.
  4. Install the new turn signal bulb. If the bulb has alignment pins on the bottom, ensure they align with the corresponding openings.
  5. Reconnect the electrical connections and replace the housing if necessary.
  6. Turn on your vehicle and test the turn signal to ensure the replacement bulb is working.

Turn signals are a vital component for driving. Signals help communicate to other drivers so that you may safely change directions, lanes or activate your emergency flashers. 

Ensuring your turn signals are operational is paramount for driving safely. A dysfunctional turn signal could earn you a traffic violation in some states! 

Leave Turn Signal Troubles to the Pros

When your turn signal starts blinking fast, it’s best to address the issue right away. If you need assistance, contact the experts at Sun Devil Auto!

We’re a complete automotive repair and maintenance company. Our ASE-Certified Technicians can handle simple turn signal bulb replacements to transmission repairs, and so much more! We offer services on most makes and models of light cars and trucks and, in many cases, same-day service. 

Whether you drive a luxury sedan, a stylish SUV, or a set of wheels that gets you from point A to point B, you can trust that your vehicle is in the right hands with us.