Turn Signal Blinking Fast – Causes, Fixes, & Cost

You may wonder, “Why is my turn signal blinking really fast”? If you notice this, the primary cause is a faulty bulb. However, other reasons, including connection issues, weak voltage, or a defective flasher relay, may be responsible.

Any electrical issue affecting the current flow through the turning signal could cause your turning signal to blink fast.

Leaving the problem unsolved could lead to the complete failure of your turning signal and serious safety issues.

What’s the Turning Signal Working Principle

A turn signal tells drivers using the road with you what direction you are going. It works with the help of a signal level or bar located on the left side of the steering wheel.

Shifting the turn bar up indicates that you will make a right turn. The right turn signal bulb or light will be activated. On the other hand, a downshift of the signal bar shows that you’re making a left turn. It activates the right signal light.

Furthermore, a complete circuit is made by raising or pushing down the turning signal bar. Current is sent from the flasher to the bulbs, which power the turn-signal light.

When activated, the sound and the flashing signal are generated from a thermal-style flasher.

A thermal-style flasher contains a bimetallic spring within the dashboard. Once the turn signal is activated, electric current flows into the device, heating the bimetallic spring.

When the bimetallic spring is heated up, the spring is bent a certain way, allowing for the complete circuit. Here, the current is sent to the outer light turning it on for a split second. It also creates the distinct clicking sound you hear.

Read Also: Car Light Types: Everything You Should Know

What are the possible causes of the Turning Signal blinking fast?

When you have a car turning signal blinking fast, it could indicate something is wrong when power runs through the turn signal relay and flows through the necessary components. You will have a steady blinking light.

Once there is a problem with the flow of electrical current, then the blinking may become faster. In some cases, the light may become fainter depending on the issue.

Many factors could cause the problem “Why is my turning signal blinking fast.” These factors include the following.

Failing bulb

A failing bulb is one of the most common causes of a turn signal blinking too fast. A turn signal bulb, when going bad, can alter the resistance of the circuits. When this happens, different currents will be sent through the blinkers.

You get a faster blinking once no constant electric current flows through the turning signal. You can easily detect this problem by testing each signal direction bulb. If one is dim or out, it could be the source of the problem.

Damaged connections

Corroded, worn, or loose connections could also alter the resistance of the current flowing through the system. In turn, it changes the blink speed of the turning signal.

Factors like rodents, power wiring, water contamination, and more could damage the connection. It is easy to find damaged wire connections; all you need to do is appropriately inspect the wires and watch out for any obvious damages.

Poor bulb quality

Installing the wrong type of bulb could also alter the resistance of the circuit, just like having a failing bulb. You must know that not all car bulbs will work for the indicator light.

For instance, if you have a fast blinking turn signal with led light installed. It means that you are driving an older vehicle. Most older cars are not compatible with LED lights and can trigger hyper-flashing.

To better understand what type of bulb will be suitable for your indicator light, check your vehicle’s manual. You will see the exact specification recommended by your vehicle’s manufacturer.

Weak voltage

Another factor that could alter the blinking of the turning signal is less voltage going into the system. Many factors could cause this, including damaged wires, circuits, and more. However, the most common cause is a drained or faulty battery.

Significant parts of the electrical components in the car rely on the battery for power, including the indicator. Once the battery is down, these components will no longer be able to function correctly.

Defective flasher relay

A defective flasher relay can cause the turning signal to blink fast. It is responsible for controlling the flashing of the turn signal. When the turning signal is activated, the flasher relay sends an electrical signal to the bulb, causing it to blink. A defective relay won’t provide a sufficient electrical signal.

Read Also: Types of Car Fuses: Everything You Need To Know

turn signal blinking fast with new bulb

How do you fix if turning Signal blinking fast problems?

To fix a fast-blinking turn signal led, you must first perform a proper diagnosis to determine the cause. As seen above, there are a lot of factors that could cause these issues.

You could physically inspect factors like the turn indicator light bulb, battery, and wiring connections. These significant factors could cause your turn signal to blink fast.

Below are ways to fix a “Why do my turn signals blink fast” problem.

Change the light bulb.

Inspect the signal direction bulbs by pushing down or raising the turn signal bar. Check both lights; if one is dim or blown out, you need a replacement.

Before you go ahead to replace the light bulb, you could consult your vehicle for the exact specification of the light bulb.

Fix or replace the wiring connection.

Your vehicle’s manual provides an exemplary diagram of the wiring connection for every component in the car. You can quickly locate the connection for the turn signal and adequately examine them.

Have the wire replaced immediately if you notice any disconnection, corrosion, exposed wire, or other damage.

Test and replace vehicle battery

If you notice that your vehicle’s electrical components are failing and you have a problem starting the car, you may have a battery problem.

You could also test the battery using a multimeter. Below is how to do so.

  • Turn off the engine and other components in the vehicle.
  • Set the multimeter to 20V DC.
  • Place the red lead on the positive terminal of the battery.
  • Place the black on the negative terminal.
  • If the measurement is below 12.4, you may need to charge your battery.

If you keep charging and the battery does not retain the charge, you may need to replace it.

Clean turn signal components

Try to clean related components of the turn signal, like the combination switch, connection, and more. It allows for a better flow of electric current through the system.

Read Also: Types of Test Light and How To Use A Test Light?

How much does it cost to fix Turning Signal blinking fast problems?

Fixing a signal blinking fast could cost from $50 to 200, excluding labor. The problem has different causes, and the cause determines the fix.

For instance, an indicator light would cost between $25 and $50. If you do the replacement yourself, it will leave you at the cost of a bulb. However, hiring a professional could cost you an extra $100 that can be compensated with an efficient fix.


In this article, we have looked at the question, “Why is my blinker blinking fast.” Now we understand that having a fast-blinking turn signal is not normal. The problem is electrical, caused by anything damage that affects the current flowing through the turn signal. And the fix can either be DIY or a premium, depending on your guts.

Akindayini Temiloluwa

I am passionate about everything automotive. Right from when I got my first toy car as a kid, I developed an interest in the inner workings of vehicles. As I grew up, my love for mechanical stuff became more substantial enough for me to pursue a career in it. My goal as an automotive content writer is to simplify the most challenging concepts for my readers, help them self-diagnose what may be wrong with their vehicles and offer real value for their time.

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