When changing lanes or moving to a neighboring street, you want to make sure your turn signals are operating as anticipated. You want other drivers to know what you plan to do next.
However, these bulbs are not free from issues. What is it that makes the turn signal blink fast, and is it a symptom that something needs to be fixed?
In this guide I will take a closer look at what causes a turn signal to blink fast, and I will share possible solutions to correct the malfunction.
Causes of Turn Signal Blinking Fast
A fast-blinking turn signal could mean you have a bad bulb. It can also be caused by not enough voltage which can mess it up. There’s also always the possibility that the turn signal fuse or relay has failed, and bad parts will need to be replaced.
Here’s a more thorough list of reasons why your turn signal is blinking fast.
#1. Bad Bulb.
The most obvious reason is a bad bulb. If one of the bulbs is damaged or burnt-out, the turn signal will blink very fast because of the change in resistance.
The turn signal bulbs are wired in parallel with one another. Because they are wired parallel to one another, the resistance is changed whenever one of the bulbs operates differently than its other companions.
#2. Insufficient Voltage.
Wiring problems usually take the lead when considering issues with automotive lights. If the power system, because of a wiring issue or battery charge, doesn’t provide enough voltage, the turn signal will “blink” fast.
Again, the ground connection affects operation. If the ground connection to a bulb or relay is pitted or worn, the turn signals do not work usually work correctly.
#3. Malfunctioning Turn Signal Relay.
When the relay malfunctions, the turn signals can speed up. Water has sometimes gotten into the relay and caused a problem; particularly if the pins are rusting.
When the relay fails the hazard lights can sometimes behave erratically. There are even times when the turn signals or hazard lights won’t turn off at all.
#4. Defective Turn Signal Fuse.
The turn signal will stop working if the fuse is defective. However, on most vehicles when the fuse blows, the turn signals stop working altogether.
You can check the fuse using the outline in the owner’s manual. It’s fairly easy to see if any of the wire is broken in a blown fuse.
Ways to Fix the Turn Signal Blinking Fast
#1. Inspect the Bulbs.
When the turn signals flash quickly, it’s necessary to look at all of the lighting to see what is happening. Look at the bulb that is flashing quickly, but also check the condition of the other lights as well.
If there is only a problem with the one bulb, then replacing it may be the next step. However, if you notice problems with multiple lights, it’s probably not the case that all of the bulbs are bad and you can skip the next step. Keep in mind to check the fender turn signal bulbs as well!
You want to always make sure the right type of bulb is installed. If there is a bulb that is installed that has the wrong resistance, then this could be a reason for the fast flashing turn signals.
#2. Replace Defective Bulb.
If you have determined it to be just one bulb, simply replace it. For some vehicles, this is a straightforward process. Other models may require you to remove a lot of parts, which will then allow you to get to the housing.
Here are some basic steps to follow:
- Open the hood of the car or trunk (depending on the bulb you need to replace).
- Remove the electrical connector from the electrical connector out of the bulb. You may need to press down the locking tab to get the connector off.
- Remove the bad bulb. This may be a simple counterclockwise twist-off, or it may pull straight out instead of twist-off.
- Get the new bulb to its position.
- Put the electrical connectors onto the new bulb.
- If it is the turn signals, test them to see if this fixed the issue.
The overall price for a new bulb is typically anywhere between $5-$10. Unless you are able to do this yourself, you will have no labor charge. Otherwise, if the bulb is trickier to get to, it may cause you on the high end about $35-$40, at a shop, to do the work.
#3. Check Wiring.
To begin with, you want to check if the battery is working properly, especially if you are having issues with any other bulbs too. If the battery is weak, it may not be able to output enough voltage to the lights. If that is the case, charge or replace the battery.
Next, you will want to check the wiring between the bulb; damaged or corroded wires can create a plethora of electrical issues. Make sure all the wires and connectors are tested for an appropriate amount of current.
You can reference your car’s service manual for more information on this. Depending on what wiring needs to be replaced, the repair can get a little expensive, but you can sometimes put some dielectric grease in the electric connectors if they are corroded.
Next, you will want to check the fuse. Pull the appropriate fuse out and check to see if the wire is broken or not. If the wire is broken, it is very easy to replace the fusible link with the same exact capacity. Only a couple of dollars to buy.
#4. Swap out Relay.
The last thing to check for is the relay. You won’t get to this stage until the bulbs test fine, and the wiring test gives you good results. When the relay is defective, you will not hear the relays clicking.
If the normal turn signal clicks when it is working, you may have a defective relay that isn’t clicking.
However, a bad relay means trouble for both signals, which makes it easier to have an answer. It isn’t always easy to replace the relay, however, so you may need a professional to help. You may only spend around $10-$20 for the relay itself.
Most of the cost is in the labor to swap out the relay assembly. If you are not able to swap out the relay yourself, you may pay an additional $35-$50 to change out the relay.