What are the possible causes of a turn signal flashing too fast?

If your turn signal is flashing too quickly, it could indicate an underlying issue with your vehicle's electrical system. In this article, we'll explore the potential causes and provide guidance on how to address the problem.

Faulty Turn Signal Bulb

One of the most common reasons for a turn signal flashing too fast is a faulty or burned-out turn signal bulb. When a bulb is not functioning properly, the turn signal relay will detect the change in resistance and cause the signal to flash at a faster rate. This is a safety feature to alert the driver and other motorists that the turn signal is not working correctly.

Malfunctioning Turn Signal Relay

The turn signal relay is responsible for controlling the timing and flashing rate of the turn signals. If the relay is faulty or malfunctioning, it can cause the turn signals to flash too quickly. This could be due to an electrical issue within the relay or a problem with the wiring connecting the relay to the turn signal bulbs.

Incorrect Turn Signal Bulb Wattage

Using turn signal bulbs with the wrong wattage can also cause the turn signals to flash too rapidly. If the bulbs have a lower wattage than the vehicle's electrical system is designed for, the turn signal relay will detect the change in resistance and increase the flashing rate. Replacing the bulbs with the correct wattage can often resolve this issue.

Loose or Damaged Wiring

Loose or damaged wiring in the turn signal circuit can disrupt the electrical flow and cause the turn signals to flash too quickly. This could be due to a loose connection, a short circuit, or a break in the wiring. Inspecting and repairing any issues with the wiring can help restore the proper turn signal operation.

Troubleshooting Steps

• Check the turn signal bulbs for any signs of damage or burnout and replace them if necessary.


• Test the turn signal relay by swapping it with a known good relay or using a multimeter to check its functionality.


• Inspect the wiring in the turn signal circuit for any loose connections, shorts, or damage.


• Ensure that the replacement turn signal bulbs have the correct wattage for your vehicle.

If the issue persists after trying these troubleshooting steps, it's recommended to have a professional mechanic diagnose and repair the problem to ensure the proper and safe operation of your vehicle's turn signals.

How do I fix a hyper blinking turn signal?

To fix a hyper-flashing turn signal, you can either install an LED-compatible flasher relay or add load resistors to the circuit. Installing a resistor is necessary when you switch to LED bulbs, as the lower power draw from LEDs tricks the car into thinking a bulb is burned out. For incandescent bulbs, the fix might be as simple as replacing a burnt-out bulb, cleaning the socket, or checking the flasher relay.
 
This video demonstrates how to install load resistors to fix hyper flashing: 20sTheRetrofitSourceYouTube · Apr 12, 2023
For LED bulbs (common cause)

• Install load resistors: This is the most common fix for LED turn signals. 
  • How it works: Resistors create the same electrical load as an old incandescent bulb, allowing the system to function correctly. 
  • Installation: Connect the resistor in line with the turn signal's power and ground wires, typically using T-taps or soldering. 
  • Important: Mount the resistor to a metal surface, as it will get hot. It should not be left loose in the plastic housing. 
• Use a "built-in decoder" or higher-power bulb: Some LED bulbs are designed to prevent hyper flashing by including a built-in resistor or drawing more power. 
• Consider an LED-compatible flasher relay: Replace the original flasher relay with one specifically designed for LEDs. 

For incandescent bulbs or general issues

• Replace the bulb: The most straightforward fix is often replacing a burnt-out bulb. Check your owner's manual for the correct replacement. 
• Clean the bulb socket: Corrosion or dirt in the socket can cause a poor connection, leading to hyper flashing. 
• Check the flasher relay: The relay itself can be faulty. For some older cars, the relay is replaceable. In other cases, a special LED flasher relay might work. 

Why are my indicators flashing too fast but bulbs ok?

A fast-blinking turn signal with a good bulb is usually caused by a problem with the bulb's resistance, often due to a burned-out bulb on the same side, a faulty flasher relay, corrosion, or incorrect bulb wattage (especially when switching to LEDs). To troubleshoot, first, double-check that the "good" bulb isn't actually faulty and then inspect the flasher relay, connections, and wiring for issues like corrosion, damage, or incorrect bulb types. 
Potential causes and solutions 
This video demonstrates how to diagnose a fast-blinking turn signal by checking the bulbs: 1mStan CravensYouTube · Nov 4, 2022

• Burnt-out bulb: Even if you think the bulb is good, it's the most common cause. Another bulb on the same side might be the issue, such as a rear turn signal bulb that is also a brake or tail light. 
  • Solution: Carefully check all bulbs on the side that is blinking fast. If one is dim or not working, replace it. If you've already replaced a bulb, you may need to check the other bulb on that side, or a separate tail or brake light on that side. 
• Incorrect bulb wattage/type: If you've recently switched to LED bulbs, they draw less power and can cause the turn signal to flash rapidly because the flasher relay expects a certain electrical "draw" from a traditional incandescent bulb. 
  • Solution: Revert to the original-style bulbs to see if the problem stops. If it does, you can purchase an LED-compatible flasher relay or load resistors to fix the issue with your new bulbs. 
• Corroded or damaged socket/wiring: Moisture or corrosion can build up inside the bulb socket or in the wiring harness, creating a poor connection and altering the electrical resistance. A detached or broken ground wire can have a similar effect. 
  • Solution: Inspect the bulb socket and the wiring connectors for any signs of rust, corrosion, or damage. Clean any corrosion with a wire brush or electrical contact cleaner. If the wiring is damaged, it may need to be repaired or replaced. 
• Faulty flasher relay: The flasher unit (or relay) is responsible for controlling the blink speed. If it's malfunctioning, it can cause a rapid blink even with good bulbs. 
  • Solution: Consult your car's manual to locate the flasher relay and see how to replace it. This is often a simple plug-and-play replacement. 
• Trailer wiring issues: If you're towing a trailer, a faulty trailer wiring harness or a burned-out bulb on the trailer can cause the vehicle's main turn signal to flash fast. 
  • Solution: Check all the lights on the trailer, not just the turn signals. 

You can watch this video to see how to check for corrosion in the bulb socket and wiring: 1m1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · May 18, 2020

How do you fix a blinker that blinks fast?

A fast-blinking turn signal is typically caused by a burnt-out bulb, so the most common fix is to replace the bulb on that side of the vehicle. If that doesn't work, other solutions include cleaning corroded bulb sockets, replacing the flasher relay, checking and repairing bad grounds or wiring, or, if you have LED bulbs, installing load resistors to mimic the power draw of a standard bulb.
 
1. Replace the burnt-out bulb 
This video demonstrates how to replace a turn signal bulb: 59sThomas of All TradesYouTube · Sep 28, 2023

• Locate the correct bulb: Turn on the working side to identify which bulb is out, then consult your owner's manual for the correct replacement bulb type and size. 
• Access the bulb: Open the hood or trunk to access the back of the light assembly. You may need to remove fasteners or pull the assembly away to get to the bulb. 
• Replace the bulb:
  • Twist the bulb socket counter-clockwise and pull it out. 
  • Insert the new bulb, making sure to avoid touching the glass with bare hands to prevent premature burnout. 
  • Twist the new bulb into the socket and re-secure the socket. 
  • Test the new bulb before reassembling the light assembly completely. 

2. Check and clean the bulb socket and grounds 
This video explains how to check the bulb socket and ground connections: 57s1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · May 18, 2020

• Inspect the socket for any dirt, corrosion, or rust, which can cause poor contact. 
• Clean any grime from the socket and the electrical contacts. 
• Check the ground wire for a bad or corroded connection and clean or repair as needed. 

3. Replace the flasher relay
This video shows how to replace the flasher relay: 59sBoostedMotorsportsYouTube · Sep 27, 2019

• Locate the turn signal flasher relay in your fuse box (check your owner's manual for its location). 
• Pull out the old relay and replace it with a new one. The new one should click into place easily. 

4. Install load resistors (for LED bulbs) 
This video demonstrates how to install load resistors for LED bulbs: 50sNestor Auto RepairYouTube · Sep 12, 2021

• If you recently installed LED bulbs, the vehicle's computer may think the bulb is out because LEDs draw less power. 
• To fix this, install inline load resistors that mimic the power draw of a standard bulb, or replace the flasher relay with an LED-compatible one. 

What causes the turn signal to flash faster?

A blinker blinking faster than normal is almost always a warning sign that a bulb has burned out on that side, though it can also be caused by issues like bad wiring, a faulty flasher relay, or incompatible aftermarket lights. The increased speed is a safety feature because a burned-out bulb creates a change in electrical resistance, and your car's system detects this and flashes the remaining lights faster to alert you that a bulb isn't working. 
This video demonstrates how to identify the cause of a fast blinking turn signal: 57sRooted and RisingYouTube · Jan 12, 2021
How to diagnose and fix

1. Check the bulbs: The most likely cause is a burned-out bulb. Turn on the turn signal for the side that is blinking fast. Then, walk around the car and check both the front and rear lights for that side. The one that isn't lit up is the one that needs to be replaced. 
2. Replace the bulb: If you find a burned-out bulb, replace it with a new one of the correct type. When handling the new bulb, use a glove or a cloth to avoid getting oil from your skin on the glass, which can cause it to burn out prematurely. 
3. Check other potential issues: If the bulbs are all good, the problem is likely more complex. 
   • Corrosion: Check for corrosion in the bulb socket, as this can interfere with the electrical connection. 
   • Bad wiring: Inspect the wiring for any damage, such as broken or frayed wires. 
   • Flasher/Relay: The flasher relay unit itself might be faulty. This is the part that makes the clicking sound, so if it seems strange, it may need replacing. 
   • Aftermarket lights: If you've recently installed aftermarket or LED lights, they may not be compatible with your car's electrical system and could be the cause. 
4. Seek professional help: If you are unable to find the cause or if you are uncomfortable with electrical repairs, it is best to take your vehicle to a mechanic to avoid further damage to the electrical system.