Troubleshooting and Fixing a Fast Blinking Turn Signal

In the world of automotive issues, a fast-blinking turn signal might seem minor, but it’s an important one to fix. This phenomenon, also known as “hyper flashing,” usually indicates a problem within your vehicle’s electrical system, specifically related to your turn signal or hazard lights.

While this isn’t a high-risk issue, it can create confusion for other drivers on the road, potentially leading to accidents. This guide will introduce you to the common causes of a fast-blinking turn signal and offer straightforward steps to diagnose and resolve the problem efficiently.

How Do Turn Signals Work?

Turn signals or indicators, are an essential part of a vehicle’s lighting system. They function by using a flasher relay, a small electrical device that interrupts the power to the turn signals causing them to flash on and off.

The flasher relay is connected to the turn signal switch, which the driver operates manually. When the switch is activated, current is sent to the flasher relay which in turn sends pulses of power to the relevant turn signal bulbs, causing them to blink.

6 Common Causes Of A Turn Signal That Flashes Fast

1.     Burned Out Bulb

This is the most common cause of a fast-blinking turn signal. When a bulb burns out, the electrical load in the circuit decreases, causing the flasher relay to cycle faster. Therefore, the first thing to check when your turn signal starts flashing rapidly is the bulbs.

Replacing a burned-out stop light on a vehicle.

2.     Incorrect Bulb Type

Not all bulbs are made equal. If a bulb with the wrong wattage is installed, it can change the load on the circuit, leading to faster blinking. Always ensure you’re using bulbs of the correct specifications for your vehicle.

3.     Faulty Flasher Relay

The flasher relay controls the rate at which your turn signals flash. If it’s faulty, it could cause the signals to flash too quickly. Replacing a malfunctioning flasher relay is usually a straightforward task.

4.     Bad Turn Signal Switch

The switch that you manually operate to signal a turn can also fail, causing a range of issues including a fast blinking signal. Diagnosing a faulty switch can be a bit more complex and might require a professional’s help.

5.     Wiring Issues

Problems with the wiring of your turn signal circuit, such as frayed wires, poor connections, or corrosion, can lead to irregular flashing. Wiring issues can be difficult to diagnose and fix without professional help.

6.     LED Upgrades Without Load Resistors

Upgrading to LED bulbs can cause hyper flashing if not installed with appropriate load resistors. LEDs draw less current than traditional bulbs, and the decrease in load causes the circuit to flash faster. Installing load resistors with LEDs can usually solve this issue.

Front LED headlights of low beam and high beam.

How To Fix A Turn Signal That’s Blinking Fast

1.     Replace Burned-Out Bulbs

Start by inspecting each of the turn signal bulbs. If you find a burned-out bulb, replace it immediately. You’ll need the correct replacement bulb for your specific vehicle model, which you can find in your vehicle’s manual or at an auto parts store. Remember to replace bulbs in pairs to ensure even lighting.

2.     Ensure The Correct Bulb Type

If you’ve recently replaced a bulb and are facing fast blinking, ensure that the replacement bulb is the correct type for your vehicle. Bulbs come with different wattages and using the incorrect one can cause hyperflashing. Cross-check the bulb specifications in your vehicle’s manual or consult with an auto parts store or mechanic.

3.     Replace Flasher Relay

If your bulbs are in working order and are the correct type, the next component to check is the flasher relay. You can find its location in your vehicle’s manual. Replacing it is usually as simple as unplugging the old one and plugging in the new one, but ensure to use a relay compatible with your vehicle.

4.     Inspect The Turn Signal Switch

If the issue persists, it might be due to a faulty turn signal switch. Depending on your comfort with automotive repairs, you may want to consult a professional for this. However, if you’re comfortable doing it yourself, you’ll need to remove the steering column cover to access the switch, remove it, and replace it with a new one.

Car interior with the steering column removed.

5.     Check The Wiring

Wiring issues can be tricky to diagnose and fix. Look for visible signs of damage like fraying, corrosion, or loose connections. If you suspect a wiring issue but can’t find the problem yourself, it’s best to take your vehicle to a professional. They have specialized tools and knowledge to diagnose and fix such issues.

6.     Install Load Resistors for LEDs

If you’ve recently upgraded to LED bulbs, you’ll likely need load resistors to prevent hyper flashing. These resistors increase the load in the circuit to mimic that of a traditional bulb. They should be installed in parallel with the LED bulbs. Be cautious as load resistors can get hot; ensure they’re mounted on a heat-resistant surface.

Is A Fast Blinker Illegal?

While laws vary by location, a fast-blinking turn signal can be considered a vehicle defect in many jurisdictions. It might not lead to a ticket directly, but it could potentially cause an officer to pull you over.

It’s also important for safety reasons, as it can confuse other drivers about your intentions on the road. Therefore, it’s recommended to fix a fast blinking turn signal as soon as possible.

Why Is My Turn Signal Blinking Twice As Fast?

Your turn signal is likely blinking twice as fast due to a change in the electrical load within the circuit, often caused by a burned-out bulb. This reduction in load triggers the flasher relay to cycle more quickly, leading to faster blinking. Turn signal bulbs, both front, and rear, should be checked thoroughly.

This might mean turning the signals on and physically going around your vehicle to inspect each one. If any are not functioning, they need to be replaced. Keep in mind that even if your vehicle’s turn signal bulbs are in pairs or clusters, if one goes out, it can cause hyper-flashing.

So it’s essential not just to replace the entire bulb or cluster but to ensure that each individual light source is functioning correctly.

While a fuse itself typically won’t cause a turn signal to blink faster than usual, a blown fuse could cause your turn signals to not work at all. Fuses are protective devices in your vehicle’s electrical system designed to interrupt the flow of electricity if the current exceeds a certain level, protecting other components from damage.

If your turn signals aren’t working and the bulbs are fine, it’s worth checking the relevant fuse. Always replace a blown fuse with another of the exact same rating. Never attempt to bypass the fuse or use one of a higher rating, as this could lead to serious damage or even a fire.

Can A Faulty Relay Cause A Fast Blinking Turn Signal?

Yes, a faulty relay can indeed cause your turn signal to blink faster than usual. The flasher relay in your vehicle is responsible for making your turn signals blink. It works by interrupting the power flow to the bulbs at a set frequency, causing them to turn on and off.

If this component is malfunctioning, it can disrupt the regular rhythm of your turn signal, causing it to blink more rapidly. If you’ve ruled out bulb issues and checked your fuses, the next step is to test or replace your flasher relay. Be sure to replace it with one that is compatible with your vehicle’s specifications.

LED bulbs can cause your turn signal to blink faster if they’re installed without appropriate load resistors. LEDs draw significantly less current than traditional incandescent bulbs, causing a decrease in the load within the circuit.

The flasher relay interprets this decrease as a bulb being out and responds by increasing the flash rate. To prevent this, you need to install load resistors along with the LED bulbs. These resistors increase the load in the circuit, mimicking that of an incandescent bulb and preventing hyper flashing.

Can Wiring Problems Lead To A Fast Blinking Turn Signal?

Yes, wiring problems can indeed lead to a fast-blinking turn signal. This could be due to frayed wires, poor connections, or corrosion. Any issues with the wires carrying the electrical current to your turn signals can disrupt the flow of electricity, causing issues like hyper flashing.

Diagnosing and fixing wiring issues can be a bit more complex than other potential causes of a fast-blinking turn signal. If you suspect you might have a wiring problem, it’s probably best to consult with a professional.

Auto service electrician wiring car maintenance.

How Do I Know If My Turn Signal Relay Is Bad?

If your turn signal relay is bad, you’ll likely experience issues with your turn signals. They might blink too fast, too slow, not at all, or they might stay on without blinking. To test the relay, you can try replacing it with a new one. If the issue is resolved, then the old relay was indeed the problem.

Alternatively, you can use a multimeter to test the relay for continuity. However, using a multimeter requires a level of understanding about electrical circuits, so if you’re not comfortable, it’s better to consult with a professional or simply replace the suspect relay.

Can I Drive My Car With A Fast Blinking Turn Signal?

Technically, you can drive your car even if your turn signal is blinking fast. However, it’s not advised as it may confuse other drivers. A fast-blinking turn signal might be interpreted as a strobe light or simply ignored due to its abnormal speed, potentially leading to accidents.

Additionally, in many jurisdictions, a malfunctioning turn signal could be considered a vehicle defect, which might attract a fine or other penalty. Therefore, it’s best to fix the issue as soon as possible.

Can I Replace A Turn Signal Bulb Myself?

Yes, replacing a turn signal bulb is typically a straightforward task that you can perform yourself. You’ll need the correct replacement bulb for your specific vehicle model, which you can find in your vehicle’s manual or at an auto parts store.

The process usually involves removing the light cover, taking out the old bulb, installing the new one, and replacing the cover. However, the exact procedure can vary depending on the make and model of your vehicle, so be sure to consult your owner’s manual or look for a guide specific to your vehicle.

How Do I Install Load Resistors For LED Turn Signals?

Installing load resistors for LED turn signals is a process that involves splicing the resistors into the wires for the turn signals. Each resistor should be connected in parallel (not in series) with the turn signal bulb – this means connecting one end of the resistor to the power wire of the turn signal circuit and the other end to the ground wire.

Be aware that load resistors can get very hot, so they should be mounted on a metal surface, away from any plastic or other components that could melt or burn. Always follow the manufacturer’s instructions for the specific resistors you’re using.

BMW LED load resistor.

How Often Should I Replace My Turn Signal Bulbs?

There’s no set interval for replacing turn signal bulbs, as their lifespan can vary widely based on factors like the type of bulb and how often you use your turn signals. However, you should replace your turn signal bulbs as soon as you notice one has burned out.

Regularly check your turn signals to make sure they’re working correctly. Some drivers make a habit of doing a quick check of all their lights, including turn signals, every time they fill up their gas tank.


A fast blinking turn signal, or hyper flashing, is more than just an annoying problem – it’s a potential safety issue that can confuse other drivers and might even lead to a fine. Fortunately, the most common causes are relatively easy to diagnose and fix, whether it’s a burned-out bulb, a faulty relay, or a recent upgrade to LED bulbs without the necessary load resistors.

However, if you’re ever in doubt or uncomfortable performing these repairs yourself, don’t hesitate to consult with a professional. Safe driving is worth the investment.

Avatar photo
About Brock Rangel

Hi, I am Brock, and I am the lead editor/photographer for TheCarColony. I have been a mechanic for over 14 years now, and I am here to spread my car knowledge across the web!