Why did my turn signal start blinking faster?

Rapid turn-signal blinking, or hyperflash, is usually a symptom that the electrical load in the signal circuit has dropped. In most cars this happens when a bulb is burnt out or when LEDs are installed without the proper resistors or flasher compatibility. A faulty relay or wiring can also cause the faster blink. In short, faster blinking is the car telling you something isn’t loading the circuit as expected and it should be checked.

What fast blinking signals

Hyperflash occurs when the turn-signal system detects an abnormal load on the circuit. This is a safety feature designed to alert you to a potential problem. While incandescent bulbs draw a predictable amount of current, LED replacements or other changes can alter the load enough to trigger a faster blink. A faulty flasher relay or control module can also cause the behavior, even if all bulbs appear to light normally. Understanding what you’re seeing helps you determine where to start your checks.

Common causes include the following:

• Burned-out bulb or a poorly seated bulb on the same side of the circuit.


• LED replacement without adding load resistors or using a compatible flasher/module, leading to reduced current draw.


• Faulty or aging turn-signal relay or electronic flasher unit.


• Wiring damage, loose connections, or corroded sockets, especially at the signal housings.

In most cases, correcting the faulty or missing load—such as replacing a burned-out bulb or adding the proper resistor for LEDs—restores normal blink rate. If the rapid blink persists after bulb replacements and basic checks, the issue may lie with the flasher relay or the vehicle’s control module, which may require professional diagnosis.

How to diagnose and fix

If you want to troubleshoot the faster blink, follow these practical steps to identify the cause and fix common problems.

1. Turn on the indicators and inspect every bulb on the affected side (front, rear, and side markers) for signs of burnout or improper seating.


2. Replace any burned-out bulbs with the correct type specified for your vehicle, then recheck the blink rate.


3. Test fuses related to the turn signals and the body control module; replace any blown fuses with the proper rating from your owner's manual.


4. Inspect bulb sockets and wiring for corrosion, looseness, or damaged insulation; clean and reseat connections and ensure a solid ground.


5. If you’ve installed LED bulbs, verify you have the proper load resistors or a CAN-compatible flasher/module as recommended by the bulb manufacturer or vehicle maker.


6. If the blink rate remains fast after these steps, consider having the flasher relay (in vehicles with a dedicated relay) or the body control module tested by a professional, as electronic faults may require specialized diagnostic tools.

Conclusion: For most drivers, replacing a faulty bulb and ensuring proper load restores normal operation. Persistent hyperflash after bulb and wiring checks points to a failing relay or control module, which should be diagnosed by a qualified technician.

Summary

Faster turn-signal blinking is typically a warning that the electrical load in the circuit has dropped—most often due to a burnt-out bulb or LED upgrade without proper load management. Start by inspecting and replacing bulbs, then check fuses, connections, and any LED resistors. If the problem persists, the flasher relay or body control module may be at fault and require professional diagnosis. Regular maintenance helps ensure you’re signaling clearly and safely on the road.

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 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 is my blinker blinking faster than normal?

A turn signal blinking faster than normal, known as hyper-flashing, most often means a bulb on that side has burned out. Other common causes include faulty wiring, corroded sockets, a bad flasher relay, or issues with aftermarket LED lights. 
This video shows how to fix a fast blinking turn signal by replacing a burnt-out bulb: 59sThomas of All TradesYouTube · Sep 28, 2023
Common causes and what to do

• Burned-out bulb: This is the most likely reason. 
  • Check: Activate the turn signal for the side that is blinking fast. Then, walk around your car to check the front and rear lights for that side and see which one is not on. 
  • Fix: Replace the burned-out bulb. You can find the correct replacement type and instructions in your owner's manual. 
• Faulty wiring or connections: This includes corroded sockets, bad ground connections, or detached wires. 
  • Check: Inspect the wiring and the socket for any signs of corrosion, damage, or loose connections. 
  • Fix: Clean the socket and wires or repair any damaged connections. 
• Bad flasher relay: The flasher unit or relay controls the blinking speed, so a faulty one can cause hyper-flashing. 
  • Check: Listen for any unusual clicking sounds from the flasher relay, which is often located under the dashboard. 
  • Fix: Replace the flasher relay. 
• Incompatible LED lights: If you've recently installed aftermarket LED turn signals, they may be causing the issue. 
  • Check: Hyper-flashing is a common problem with LEDs that are not compatible with the car's system. 
  • Fix: Use LEDs with a built-in resistor or install load resistors to match the original bulb's electrical load. 
• Other issues: Less common causes include a bad fuse, a failing alternator, or the wrong type of bulb being installed. 
  • Check: Ensure all fuses are good, and have your alternator tested if you suspect it's failing. 
  • Fix: Replace any blown fuses or address the underlying problem. 

This video explains the common causes of a fast blinking turn signal: 1mStan CravensYouTube · Nov 4, 2022

Why are my indicators flashing 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