Home » Brands » Ford » Why Is Your Ford F-150 Blinker Blinking Fast?

Why Is Your Ford F-150 Blinker Blinking Fast?

Realizing that your blinker is blinking much faster than usual can be quite confusing and even concerning. 

Blinker blinking too fast in a Ford F-150 is not usually a serious problem. In most cases, it simply means there is an issue with one of the bulbs on the corresponding side of the vehicle. 

5 Reasons a Blinker Will Blink Fast in a Ford F-150 and How to Fix It

A black Ford F-150 parked in the forest in the daytime with blinkers on.

A fast blinker in your Ford F-150 can mean a few different things. 

So, in this article, I will describe some of the reasons why your F-150’s blinker is blinking fast and how you can fix each possibility. 

1. One of Your Bulbs Has Gone Out or Is About to Go Out 

The most common reason the blinker will blink fast in a Ford F-150 is that one of the bulbs has gone out or is about to go out. 

To determine if the bulb is causing the problem, you should first turn the blinker on to the side that blinks fast. 

Then, get out of the car and examine the bulbs on that side of the vehicle. 

If you notice that one of the bulbs is out, you should replace it. 

Afterward, try the blinker again and see if it still blinks fast. 

If it doesn’t, you’ve solved the problem. 

If it continues to blink rapidly, you may want to replace all the bulbs on that side of the vehicle because it could be that one of them is dying out. 

Again, you should turn the blinker on after replacing the bulbs to see if the problem is gone. 

If not, try another solution. 

2. Your Relay Switch Is Not Working Properly 

Relay switches help protect your vehicle’s circuits by ensuring they don’t get too much current at once. 

However, over time, these switches can go bad, and a rapid blinker is one of the first indications that a relay is dying. 

To determine if a relay switch is about to expire, you first need to find the fuse box in your vehicle. 

And the location of the fuse box in your F-150 depends on the year. 

For F-150s made between 1997 and 2003, you will find the fuse box to the left of the steering wheel near the brake pedal. 

In 2004-2022 F-150s, the fuse box is underneath the glove compartment on the right side. 

Then, once you have located and exposed the fuse box, you will have to figure out if it is indeed the relay switch that is causing the problem. 

One way to determine this is by swapping the bad relay with a working one. 

Just make sure you exchange the relay with an identical one that has the same numbers on it. 

If you swap the relays and the blinker works normally, you now know you need a new relay. 

Alternatively, you can check the relays by plugging a relay tester into your F-150’s battery. 

If the tester produces a red light, one of your relays is bad. 

3. You’re Using the Wrong Bulb 

If you notice your turn signal blinking rapidly after changing a light, you might have installed the wrong bulb. 

So, make sure all the bulbs in your car fit with your lighting system. 

In particular, bulbs that add too much additional lighting can make your blinker blink fast. 

4. Your Alternator Is Overcharging Your Battery 

One of the more severe issues that a fast blinker can indicate is that your alternator is overcharging your battery. 

You see, your alternator is responsible for converting the mechanical energy in your car to electrical energy so that the electrical components of your vehicle can work properly. 

But, if your alternator produces too much energy, it can overcharge the battery and disrupt the electrical systems in your car. 

Besides a fast blinker, some of the ways you can tell if your alternator is overcharging your battery include: 

  • Your battery’s swollen 
  • Your lights sometimes get abnormally bright 
  • Your lights blow out quickly 
  • Your battery gets excessively hot 
  • Your battery is leaking 

If you believe your alternator is not working, you should get it fixed as soon as possible to prevent further damage to your truck. 

5. There Is a Bad Ground Connection 

If there is a bad ground connection to your battery, the electrical equipment in your vehicle won’t work correctly. 

To check your ground connection, you should look to see if any wires in your car are frayed or loose. 

If they are, this may be the cause of your fast turn signal. 

You should also check your battery’s ground terminal to ensure nothing is out of place. 

If you want to be sure you don’t have a bad ground connection, you can use a digital multimeter to check your grounds. 

Is a Fast Blinker Illegal?

A blinker that blinks too fast is illegal since it can distract other motorists. 

According to the Department of Transportation, your blinker should not blink more than 120 times per minute. 

If your blinker does not blink this fast, you shouldn’t get pulled over for it. 

Is a Fast Blinker Distracting?

A car parked on a foggy road during sunset with its blinkers on.

Yes, a rapid blinker can be distracting to you and other drivers on the road. 

And any type of distraction when driving can lead to an accident. 

Thus, you should fix your fast blinker as soon as you can. 

How to Change a Turn Signal Bulb in a Ford F-150

Changing the turn signal bulb in a Ford F-150 is quite easy, but exactly how you must change it depends on whether the defective bulb is in the front or the back of the vehicle. 

How to Change a Front Turn Signal Bulb in a Ford F-150

To change the front turn signal bulb in your Ford F-150, follow these steps: 

  1. Open the hood 
  2. Unscrew the rubber seal next to your headlight
  3. Fold the rubber seal back so that you can access your lights
  4. Unscrew the bolt underneath the rubber seal and the two on top of your headlight
  5. Gently pull out the headlight and detach it from its connections
  6. Find the turn signal light, twist it counterclockwise, and pull it out
  7. Install the new turn signal bulb by pressing it into the spot where you just removed the previous bulb and turning it clockwise half a turn
  8. Reconnect the headlight
  9. Tighten all the bolts you unscrewed
  10. Secure the rubber seal
  11. Close the hood

How to Change a Rear Turn Signal Bulb in a Ford F-150

To change the rear turn signal bulb in a Ford F-150, you must: 

  1. Open the tailgate 
  2. Remove the bolts on the side of the light protector panel (the plastic that protects the lightbulbs)
  3. Standing at the back of the car, pull the light protector panel straight towards you until it comes off
  4. Find the faulty bulb and turn it until it pops out
  5. Replace the bulb  
  6. Push the light protector panel straight back into its slot and ensure it’s on tight
  7. Re-screw the bolts on the side of the light protector panel
  8. Close the tailgate 

How Much Is a Turn Signal Light for a Ford F-150?

A close-up photo of a vehicle's headlamp and signal lights.

You can generally expect to pay between $8 and $26 for two turn signal light bulbs for your Ford F-150. 


In most cases, your F-150’s blinker is blinking too fast because one of the bulbs is out or about to go out. 

Yet, it could also be due to a dying relay switch, an incorrect bulb, a faulty alternator, or a bad ground connection.

Similar Posts