Do these fit all trims and headlight configurations?

Yes for halogen-equipped F-150 trims (XL, STX, XLT) using 4257 sockets. Always verify bulb type, as higher trims or LED headlight packages may differ in configuration.

How do these compare physically to OEM 4257 / WT21/7W bulbs?

Equivalent base size and seating depth, designed to match OEM tolerances. LED housing is compact, ensuring proper locking and alignment without looseness or fitment issues.

How do I install a LED turn signal?

Installing Switchback LED turn signal bulbs can be an easy and straightforward process: Locate and safely remove your existing turn signal bulb Unplug the old bulb from its connector Plug in your new Switchback LED bulb Test the lights to ensure proper white and amber operation Secure the bulb housing back in place Most installations take just minutes per side with no special tools required. If you experience any flickering or error messages, our included load resistors can easily resolve these issues.

Do these install perfectly on 2020–2023 F-150 without modification?

Yes. 4257 bulbs match OEM base dimensions, ensuring direct fitment into factory sockets. No trimming, forcing, or socket modification required under normal installation conditions.

Should I install a white LED or a red LED behind a red lens?

You can install either color, but it’s best to use a red LED behind a red lens. When using red LEDs for underground lighting, you’ll achieve a bright, deep red color projection. In contrast, if you place a white LED behind a red lens, the result will be a washed-out, soft pink color projection.

Will the LED burn or melt the lens of my headlight or taillight?

No LEDs run cooler than OEM bulbs and will not harm or cause any damage to your wiring harness or housings. And our LEDs have an advanced cooling system, making it efficient and durable with a lifespan of 25k+ hours

Does this aftermarket LED replacement bulb with built-in resistors get hotter than the OEM bulb?

No, the LED does get hot, but not as hot as an incandescent bulb.

Does our rear brake and turn signal bulb with built-in resistors work on taillights with 2 bulbs in each taillight?

Yes, ours is unique and different from other competitors. Unlike other brands out there that don't work, ours will. We specially designed the circuit board to work with the BCM.

Do you offer free shipping?

Yes, we offer free shipping on orders over $89.

How to confirm 4257 vs 7443 socket on your truck?

Check one of these: Owner’s manual (bulb size section) Remove existing bulb → 4257 = dual contact pins (offset), 7443 = wedge base Match with OEM spec for front turn signal/DRL circuit 2019 is a split year—both types exist depending on trim

I got my LED with built in resistors and I still have hyper flash why?

Did you start the engine before testing? The vehicle engine must be on and running for the BCM to turn on for the load resistors to be detected. Read the Hyperflash guide & know the details

Should I install a white LED or a red LED behind a red lens?

You can install either color, but it’s best to use a red LED behind a red lens. When using red LEDs for underground lighting, you’ll achieve a bright, deep red color projection. In contrast, if you place a white LED behind a red lens, the result will be a washed-out, soft pink color projection.

Do these fit all trims and headlight configurations?

Yes for halogen-equipped F-150 trims (XL, STX, XLT) using 4257 sockets. Always verify bulb type, as higher trims or LED headlight packages may differ in configuration.

Will the LED burn or melt the lens of my headlight or tail light?

No LEDs run cooler than OEM bulbs and will not harm or cause any damage to your wiring harness or housings. And our LEDs have an advanced cooling system, making it efficient and durable with a lifespan of 25k+ hour

Does this aftermarket LED replacement bulb with built in resistors get hotter than the OEM bulb?

No, the LED does get hot, but not as hot as an incandescent bulb.

Does our rear brake and turn signal bulb with built in resistors work on taillights with 2 bulbs in each tail light?

Yes, ours is unique and different from other competitors. Unlike other brands out there that don't work, ours will. We specially designed the circuit board to work with the BCM

How do these compare physically to OEM 4257 / WT21/7W bulbs?

Equivalent base size and seating depth, designed to match OEM tolerances. LED housing is compact, ensuring proper locking and alignment without looseness or fitment issues.

Do these install perfectly on 2020–2023 F-150 without modification?

Yes. 4257 bulbs match OEM base dimensions, ensuring direct fitment into factory sockets. No trimming, forcing, or socket modification required under normal installation conditions.

Do you need FORScan to disable bulb-out detection?

No—built-in resistor handles load simulation. Prevents hyperflash Maintains correct flash rate (60–120 flashes/min standard) Works with factory BCM without coding FORScan not required in normal conditions.

How to confirm 4257 vs 7443 socket on your truck?

Check one of these: Owner’s manual (bulb size section) Remove existing bulb → 4257 = dual contact pins (offset), 7443 = wedge base Match with OEM spec for front turn signal/DRL circuit 2019 is a split year—both types exist depending on trim

Do you offer free shipping?

Yes, we offer free shipping on orders over $89.

I got my LED with built in resistors and I still have hyper flash why?

Did you start the engine before testing? The vehicle engine must be on and running for the BCM to turn on for the load resistors to be detected. Read the Hyperflash guide & know the details

1 17

SKU: F150-Rear-21

2021–2025 Ford F-150 4257 Red LED Tail/Brake & Rear Turn Signal Bulbs (Pair) – Built-In Resistor, No Hyperflash

Name: 2021–2025 Ford F-150 4257 Red LED Tail/Brake & Rear Turn Signal Bulbs (Pair) – Built-In Resistor, No Hyperflash
Brand: Underground Lighting
SKU: F150-Rear-21
Price: 69.99 USD
Availability: InStock
Rating: 4.92 (104 reviews)

$69.99

Popular right now
Lots of people have looked at this recently

300% brighter than halogen for clearer braking and rear turn signal visibility
The built-in resistor eliminates hyperflash instantly.
Fan + metal heatsink cooling system extends lifespan up to 10x longer.
4257 plug-and-play replacement, no cutting, wiring, or required
Designed for compatible 2021–2025 Ford F-150 trucks with replaceable rear bulb sockets
Designed in the USA, assembled with Japanese components

Live Chat With a Qualified Expert

Description

Why These 4257 LED Brake & Tail Light Bulbs Stand Out

Our F150 brake light competes with sunlight, rain, and surrounding vehicles. Compared to Halogen bulbs that put out roughly 300 to 400 lumens, our LED tail light bulb delivers 1600 lumens for maximum brightness and faster reaction time.
Direct replacement for compatible 2021–2025 Ford F-150 rear lights. These red 4257 LED bulbs are designed for Ford F-150 configurations that use replaceable rear brake, tail, and turn signal bulbs. Always verify your factory bulb and taillamp configuration before ordering.
12 high-power LEDs produce 1600 lumens across a full 360-degree beam angle, so your rear light bulbs stay visible from behind and from the side. That means clearer braking, cleaner lane-change signaling, and better collision awareness for everyone around you.
The dual-intensity 4257 design supports brake, turn, and parking functions, switching between low and high output instantly to ensure clear signal separation and faster driver recognition.
LED bulbs draw less current than halogen bulbs, which can trigger rapid blinking. The built-in resistor simulates factory load (~60–120 flashes/min), restoring correct flash rate without external resistors.
Excess heat reduces LED efficiency and lifespan. Our Ford F-150 LED rear signal bulbs include a fan and metal heatsink system to regulate temperature, maintaining stable brightness and extending lifespan up to 10× longer than halogen bulbs.
CANBUS, non-polar, and CK-compatible electrical design helps simplify installation and supports proper operation with compatible factory sockets.
Designed in the USA with Japanese components for consistent electrical and thermal performance.
Plug-and-play Installation takes approximately 10 minutes. The bulbs install directly into the factory socket without cutting, splicing, or modifying the vehicle wiring.

For installation instructions, use the Installation & Tutorial tab or watch the installation video provided on this page.

CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

Do you have questions about the application, installation, shipping, warranty, or more? Do not hesitate to reach out to Underground Lighting and talk to a specialist. Chat with us online by hitting the chat button or call us at (561) 918-5225. We are here to help!

What's Included

What's Included
Bulbs	2 × 4257 Red CANBUS LED Bulbs with Built-In Resistors
Warranty	Includes a 1-Year Manufacturer Warranty covering defects under normal use.

Product Information

LED Chips - 12 High-Power Red LEDs

Variant - 4257

Function Brake / Turn / Parking (3-in-1)

Beam Angle - 360° Coverage

Color - Red

Cooling System - Fan + Metal Heatsink

Electrical Design - CANBUS, Non-polar, CK Compatible

Hyperflash - No (Built-in resistor)

Installation - Plug & Play

Quantity - Pack of 2

Tech Specs

Tech Specs
Wattage	27W
Length	2.4 in
Diameter	0.83 in
Intensity	1600 Lumens

Videos

Warranty Information

This product has a 1 year warranty

Installation & Tutorial

Download Installation & Tutorial PDF

Installation Video

Frequently Asked Questions (FAQ)

How much does the Ford F-150 4257 Red LED Rear Brake & Turn Signal Bulb replacement cost?

The Ford F-150 4257 Red LED Rear Brake & Turn Signal Bulb replacement costs $69.99 for a pair. These red LED bulbs are designed for rear brake and turn signal use, with built-in resistors to help prevent hyperflash.

How can I choose the right bulb size for my Ford F-150?

Check your F-150’s model year, trim, factory tail-light configuration, and socket type from vehicle owner’s manual before choosing a bulb. For compatible 2021–2025 F-150s with halogen-equipped rear lights, this product uses a 4257 socket. Higher trims or factory LED configurations may use different lighting setups, so verify fitment first.

What type of taillight bulb is compatible with a 2021 Ford F-150?

For a 2021 F-150 with halogen-equipped rear lights and a 4257 socket, a 4257 bulb is compatible. This Underground Lighting LED provides red brake, turn, and parking functions with a built-in resistor. Trim and factory LED configurations can differ, so confirm your original socket before ordering.

Is the Ford F-150 tail light bulb replacement worth it?

For a compatible F-150 using replaceable 4257 halogen bulbs, upgrading can provide significantly brighter rear lighting at a lower cost, along with a plug-and-play solution.

This 4257 LED produces 1600 lumens, has 360° coverage, built-in resistor technology, and requires no external resistor. Check your trim and factory lighting configuration first.

What size bulb does a 2022 Ford F-150 use for the brake light?

A compatible 2022 F-150 using a 4257 rear bulb socket can use a 4257 brake-light bulb. However, bulb requirements can vary with trim and factory lighting configuration, so verify your existing socket before replacing it.

What brake light bulb type does the 2023 Ford F-150 use?

For compatible 2023 F-150 applications with a replaceable 4257 socket, the brake light uses a 4257 bulb. Underground Lighting specifically lists the 4257 LED for the 2023 F-150 and STX. Other trims or factory LED configurations may differ, so verify the original bulb and socket before ordering.

What rear tail light bulb size does a 2021–2025 Ford F-150 use?

The rear tail light, brake light, and turn signal on a 2021 to 2025 Ford F-150 use a WT21W/7W-style dual-intensity 4257 bulb. This applies to halogen-equipped trims like the XL, STX, and XLT. Higher trims or models with factory LED tail lights may use a different setup, so check your factory bulb before ordering.

Do the built-in resistors make these LED bulbs hot?

The resistor and LED components generate heat during operation. These bulbs use an integrated fan and metal heatsink to manage that heat.

Always make sure the bulb is fully seated, has adequate clearance inside the housing, and is installed only in a compatible application.

Will these 4257 LED bulbs fit every 2021–2025 Ford F-150 trim?

No. They only fit halogen-equipped trims like the XL, STX, and XLT, since these use the 4257 socket. Higher trims or models with factory LED taillights may use a different setup, so check your bulb type before ordering.

Will these bulbs work in a taillight that uses more than one bulb?

Fitment depends on the specific socket and function, not simply the number of bulbs inside the taillamp assembly.

If the brake/tail/turn position you are replacing uses the compatible 4257 / WT21-type socket, you can use this bulb for that position. Confirm the factory bulb before ordering.

Will these bulbs work in a taillight that uses more than one bulb?

Fitment depends on the specific socket and function, not simply the number of bulbs inside the taillamp assembly.

If the brake/tail/turn position you are replacing uses the compatible 4257 / WT21-type socket, you can use this bulb for that position. Confirm the factory bulb before ordering.

How do I confirm that my F-150 uses the correct 4257 rear bulb?

Check your:

Vehicle owner's manual
Existing rear bulb marking
Factory bulb socket
Vehicle fitment result on this page

The rear lamp must use a replaceable 4257 / WT21-type bulb. Factory full-LED taillamps are not compatible with this replacement bulb.

I installed the bulbs and still have hyperflash. What should I check?

Start the truck and test the turn signals again so the vehicle's lighting control system is fully active.

If hyperflash remains:

Confirm both bulbs are fully seated.
Check the electrical connections.
Make sure the truck uses the compatible replaceable-bulb rear lamp configuration.
Verify that the correct brake/turn socket was replaced.

Compatibility

Compatibility
Cross-compatibility	4257, 4257NA, Wt21
Fitments	2025 Ford F-150 Brake Light, 2024 Ford F-150 Turn Signal Rear, 2023 Ford F-150 Brake Light, 2023 Ford F150 STX Brake Light, 2023 Ford F-150 Turn Signal Rear, 2022 Ford F-600 Super Duty Rear Turn Signal, 2022 Ford F-550 Super Duty Rear Turn Signal, 2022 Ford F-450 Super Duty Rear Turn Signal, 2022 Ford F-350 Super Duty Rear Turn Signal, 2022 Ford F-250 Super Duty Rear Turn Signal, 2021 Ford F-600 Super Duty Rear Turn Signal, 2021 Ford F-550 Super Duty Rear Turn Signal, 2021 Ford F-450 Super Duty Rear Turn Signal, 2021 Ford F-350 Super Duty Rear Turn Signal, 2021 Ford F-250 Super Duty Rear Turn Signal, 2022 Ford F-150 Brake Light, 2021 Ford F-150 Brake Light, 2022 Ford F150 STX Brake Light, 2021 Ford F150 STX Brake Light, 2022 Ford F-150 Turn Signal Rear, 2021 Ford F-150 Turn Signal Rear
Circuits	12V
Blinker Circuits	Built-In Resistor

Payment & Security

Payment Methods

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

45 Day Returns

Hassle-free & easy
Talk to a Specialist

Call us (561) 918-5225
Free Shipping

On orders over $99.99
Ships Same Day

If order is placed before 2PM EST

5 stars: 96 (92%)
4 stars: 8 (8%)
3 stars: 0 (0%)
2 stars: 0 (0%)
1 star: 0 (0%)

Much brighter!

Received bulbs within 1 week. Installation took 10-15 minutes. Much brighter! No hyperflashing or error codes. Here are some additional notes: When installing the bulb into the socket, make sure they are fully seated. It may look and feel like they are seated, but if they don't illuminate then they may require an additional push about 1/8" to fully seat the bulb into the socket. Very tight fit. So tight that it expands the socket just enough that it is difficult to reinsert back into the taillight assembly without applying additional pressure. The cooling fans operate only when the bulb is bright (brake light or turn signal). When the brake is applied the fans run continuously and when the turn signals are used they cycle on and off to match the blinking. The fans are not silent, but can be heard when in operation and standing by the rear of the truck. When backing up in reverse, the rear-view camera will show significantly more red in the image when the brake is applied than with the stock incandescent bulb. Still a good image, just more red.

Awesome

These are better then expected!! Installed when sun was up and even in direct sunlight, they are very bright. (Light on Left)

2021-24 Ford F150 Red Rear Brake/ Turn Signal LED Bulb W/ Built in Resistor No hyperflash (PAIR)

It is fantastic! I go it for my 2024 F150 XLT 303A pkg with one bulb on each tail light. Everything is as described. Easy installation. No slight delays in lighting reaction timing like other competing brands, No hyperflash as well. Now let's hope the bulbs are long lasting. Very satisfied so far.

Awesome quality! Safer, brighter, great upgrade!

Installed on my XLT, & they do excellent as described, I’ll be buying again for my fleet F150’s

GREAT BRIGHT LEDs

Very easy to install and are VERY bright. I have A built in flasher on my 2021 STX f-150 and it worked great!

Brake and turn LED’s

They install seamlessly work flawlessly, no hyper flashing and you can barely notice there is even a slight hum. Highly recommend! Pic shows LED bulb on top and oem halogen on bottom for comparison!

Brake and turn LED’s

They install seamlessly work flawlessly, no hyper flashing and you can barely notice there is even a slight hum. Highly recommend! Pic shows LED bulb on top and oem halogen on bottom for comparison!

Good lights

Super bright! The resistor in one bulb failed after 2 years, and because they are sold in pairs the replacement cost was 2X. But for that, I’m happy with the bulbs.

2021–2025 Ford F-150 4257 Red LED Rear Brake & Turn Signal Replacement Bulbs for 3X Visibility | 300% Brighter 1600LM (PAIR) | Built-in Resistor, No Hyperflash

Only lasted about 2 years

Only lasted about 2 years. That’s relatively short. But so bright and easy to install I decided to buy replacements. Hopefully, the replacements will have a longer lifespan.

HI, On avg they last 2-3 years as they have resistors and that causes heat. Resistors dont last for ever unforently. Without them they would last but then you would have hyperflash.

2021-25 Ford F150 Red Rear Brake/ Turn Signal LED Bulb W/ Built in Resistor No hyperflash (PAIR)

24 F150 Powerboost xlt

The bulbs are great, a hundred times better quality than the f150 led's. The main problem is: the base of the bulb is wider than the socket, if you force it the socket is expanding - almost to cracking, this doesn't let the socket to slide into the housing. You will have to send both sides- left and the right with a millimeter from each side in order to fit. A fine metal file is doing the job. One more time, the bulbs are great, in my opinion the best on the market.

No Hyperflash

Works great, no hyperflash

2021-25 Ford F150 Red Rear Brake/ Turn Signal LED Bulb W/ Built in Resistor No hyperflash (PAIR)

Wow!!! Amazing LEDs ! Suoer bright! The only thing is that these were a millimiter too big compare to the stock housing so i had to force it a bit to install them into the socket. But they work great and the hosusing was fine.

2021-25 Ford F150 Red Rear Brake/ Turn Signal LED Bulb W/ Built in Resistor No hyperflash (PAIR)

Ford F150

Thank you for your service. Lites look awesome on the truck. Thanks again

Great company to deal with

Love your product. The only issue that I have had is that after about a year some of the individual led squares stop working and I have to replace the bulb.

3rd set of led brake lights!

First set lasted 4 months, got too hot and the led chips came off and the bulbs went into hyper flash. That was covered under warranty. 2nd set lasted about 2 years then went hyper flash. This is my LAST set. Too expensive to replace every couple years. I thought an led would last a lot longer!

Exactly what I was expecting

This is my second order; I’m happy with the purchase. And the Customer Service.

2021-24 Ford F150 Red Rear Brake/ Turn Signal LED Bulb

High-quality, super-bright bulbs. A must-have for your F150. Replaces your factory incandescent bulbs. What I like most is that you don't need to connect resistors; they're built into the bulb. Another plus! Fast shipping.

2021-24 Ford F150 Red Rear Brake/ Turn Signal LED Bulb W/ Built in Resistor No hyperflash (PAIR)

Better than expected

They were an easy install. I was pleasantly surprised how much better the light was. I would buy again

2023 F150 STX 4x4 - Tail/Brake Light

These LEDs do not disappoint! Tail light/brake light combo are definitely bright and will get anyone’s attention. No hyper flash, which is what I was looking for without adding an additional resistor. Will be ordering the full line up soon!

21 150

Very well made products well buy again