Turn Signal Blinking Fast? 4 Reasons


The turn signal is one of the most important devices in a car, it signals other drivers of your moves to keeps both you and others safe. If you searched for this article, you’ve probably noticed that your turn signal started blinking faster than normal, so why is that? and should you worry?

If your turn signal is blinking fast, it usually means one of your bulbs is blown, or close to being blown, but it could also be anything from the socket itself to the turn signal switch or bad connections, although less likely. Typically the blinking is pretty inconsistent or just blinks twice as fast

But as with all things, it might not be as simple in your case. Below, you will find a complete guide as to why your turn signal is blinking fast, including how to fix the problem

So… Why is My Turn Signal Blinking Fast?

If you are you wondering what is causing your turn signal to blink fast, or why both turn signals are blinking, knowing whether just one or both turn signals are blinking fast is the first place to start.

What you will find is that if just one turn signal is blinking fast, then most likely you just need to replace the bulb for whichever turn signal it is that is blinking fast.

The way that your turn signal is set up is pretty unique. The blinking action is caused by a flashing unit attached to your lights. The resistance leads to perfectly timed blinking. When the bulb begins to fail, it leads to a lessened resistance, causing your turn signal to blink faster.

Hearing or noticing that your turn signal is blinking faster is a sign that something needs to be addressed. Like we mentioned, the majority of the time, you just need to replace the bulb. However, there are times that there could be something else causing a problem that you need to be aware of.

To determine if your turn signal blinking fast really is just a bulb that needs replaced, test all of your signals to see if there are any other problems. You should also look for things like a broken filament, or even cloudy glass (blown fuses) that could be leading to an issue.

Turn signal bulbs

1. Faulty Bulb

As said earlier, the #1 cause of fast turn signal blinking is a faulty bulb, which would require replacement.

If you are curious to know why a faulty bulb causes the turn signal to blink faster: Generally, It's because the resistance of the bulb no longer exists in the in the circuit.  The turn signal bulbs are wired in parallel, so when the current is going through both, the relay cycles at its normal pace.  But when only one bulb is connected (because the other one is faulty), the relay receives more current, causing it to cycle faster. 

While you may never have had to change a bulb for your turn signal before, it’s usually pretty simple. In fact, some car parts stores will actually help you change it out on the lot when you purchase the bulb if you need it.

Every car is different so we can’t really tell you the exact steps to change your bulb. Most of the time, an owner’s manual will give you instructions as to how to properly remove the casing, replace the bulb, and then replace the casing.

Be sure to follow the instructions that are specific to your car so that you know if there are any specific steps you will need to follow in order to successfully change your bulb.

Once the new bulb is in place, test your signals again to determine whether the problem persists. This may help you understand if there is a bigger problem at play.

Remember that the majority of the time, turn signals blinking fast are an indication that the bulb needs replaced. However, that is not always the case so you need to consider some alternative that might be a problem.

Flasher relays

2. Bad Flasher Relay

Your turn signal requires a flasher relay in order to produce the blinking intervals for proper operation. Usually, when a flasher relay gets old, it will simply quit working. But sometimes it will start flashing erratically instead.

Either way, it is in need of replacement. This is fairly easy to do, as it is tantamount to replacing a fuse. Consult your manual for the location. Typically, they are located either under the dash or in the engine compartment.

3. Electrical Connection Issues

Next, the issue could be the ground connection. This is typically indicative of a blown fuse, but it could also be a sign that a wire or element has gone bad as well.

Related About Fuses: Why Won’t My Windshield Washer Fluid Come Out?

But, here’s the good news! Sometimes, a ground connection that simply isn’t making connection might also just be because it’s dirty and needs a good cleaning. Check the ground connections, clean them up safely, and see if that helps.

Look for things like loose or incorrectly installed screws. This could cause the connection to become loose, which could lead to turn signals blinking fast.

This could be a fairly broad category so be sure to check all of the parts and pieces to determine just what might be causing your problem.

Check out the wires, looking closely for things like fried wires, worn wires, or even corrosion on or around the wires. Look for a loose connection. If it’s loose, you may find that sometimes it works just fine while other times it doesn’t.

You can typically replace any of the components that we’ve listed here fairly easily. You can find tutorials from a trusted mechanic and try to fix it on your own, but you can still leave it off to the professionals if you don’t want to do it yourself.

If you decide to try to replace parts on your own, always be sure you are using the right part. This is perhaps one of the biggest problems people run into. Using a cheap, knockoff part might actually lead to added problems in the end.

Poor wiring connections can cause turn signal to blink fast

To summarize, check these things for a possible bad connection

  • Fuses
  • Loose screws
  • Loose wires
  • Dirty wires or pieces
  • Corroded wires
  • Fried wires
  • Worn wires or parts

4. Poor Lighting Problems Can Cause Fast Blinking Turn Signal

Maybe you are noticing that both turn signals are blinking fast or that your lights are dimming throughout your car. We’re not just talking about your headlights and taillights. If you’re wondering why both turn signals are blinking fast or the lights in your car seem dim, there is probably a bigger issue than just a bulb.

One thing that you should be aware of is that aftermarket parts sometimes are not effectively designed for the system you have. You need to be mindful that any part you are putting in really is made to be compatible with your system. Otherwise, it can affect your entire car.

However, the parts obviously aren’t the problem if you haven’t changed any parts on your car. Here are some other signs you might notice in a poor lighting situation.

Dim Interior Lights

If you’re noticing that interior lights, like your overhead lights, are dim this could be a sign of a larger electrical problem at work. But it also might be an indication that your battery needs to be replaced or that something is not firing correctly with the alternator.

The best way to determine the issue is to have your battery voltage tested. If the voltage is low, you can try replacing your battery or perhaps have your alternator checked out. It’s better to take action now than to wait until the battery or alternator fail you!

Related: How Long Can a Car Battery Sit Unused?

Flickering Lights

Maybe you’ve been noticing flickering lights on your dashboard. This is certainly a sign of electrical malfunction. It could be as simple as the alternator. If you’re not familiar with the alternator, it is the part of your vehicle that charges your battery and helps it to hold a charge so that your vehicle can function as it is intended to.

When the alternator isn’t working properly, it can lead to all sorts of other issues as well. If you’re seeing flickering or dim lights, it is an indication that the alternator is struggling to keep up or that your battery is going bad. Essentially, it means that the battery isn’t able to hold a charge like it should.

Other accompanying signs could be slow turnovers, no cranking, grinding, freewheeling, unusual sounds coming from the battery or belts, battery light indicators on your dash, or flickering and dim lights.

Related: Why Car Lights Flicker And How To Fix It

How to Fix Turn Signals Blinking Fast

Once you’ve narrowed down the issues to figure out why your turn signals are blinking, it’s time to take action. If you feel like you have an unidentified electrical issue, we recommend that you get it checked out by a mechanic as soon as possible. For an issue such as that, you don’t want to wait to get the problem fixed as you might end up with bigger problems.

The most important thing is to troubleshoot and identify the issue. But generally, these will help fix a turn signal that is blinking too fast:

  • Changing your bulb,
  • Changing fuses
  • Cleaning the area around involved components
  • Checking your wires, even on your own.

Your owner’s manual most likely provides instructions for this process. If you are not comfortable, you should work with a mechanic.

Checking your battery and changing your battery is another action that you can tackle on your own as well. If you are not able to test your battery, most stores that have batteries do have the ability to test your battery as well.

If there is a bigger issue at play, like a potential electrical problem, you should definitely work with a mechanic.


Don’t panic if your turn signal is blinking fast! The majority of the time this is a quick and easy fix that only requires changing a lightbulb. However, you should be aware of identifiers that could be a sign of a larger issue so that you can get that addressed as soon as possible.

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