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 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 does the amber color appear in DRL vs turn signal mode?

Amber output remains consistent in color, with lower intensity in DRL mode and full brightness during signalling, ensuring clear contrast and visibility through clear lenses.

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.

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

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SKU: 4257-F150-A

2020–2023 Ford F-150 LED Front Turn Signal Replacement Bulbs | 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)

Name: 2020–2023 Ford F-150 LED Front Turn Signal Replacement Bulbs | 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)
Brand: Underground Lighting
SKU: 4257-F150-A
Price: 64.99 USD
Availability: InStock
Rating: 4.93 (87 reviews)

$64.99 $69.99

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300% brighter than halogen for clearer signaling
Built-in resistor eliminates hyperflash instantly
Advanced cooling extends lifespan up to 10× longer
4257 plug & play, zero wiring required
Designed in USA, assembled with Japanese components

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Why does this Ford turn signal bulb beat everything else?

Underground Lighting Ford F-150 front turn signal bulb replacement is a direct-fit 4257 LED upgrade with CANBUS compatibility. Plug-and-play installation into a factory socket. No wiring, no modification & no external load resistor required.
The amber output is designed for the Ford F-150 front turn signals, giving you a clear, high-contrast signal in both DRL and turn-signal operation. It is a legitimate color in multiple states.
Direct Fit for 2020-2023 Ford F-150 Models, check compatibility for fitment details.
With 54 SMD LEDs and 360° coverage, the bulb spreads light across the front and side angles for more consistent visibility during turns and lane changes.
The built-in resistor is designed specifically for the turn signal circuit. It compensates for the lower current draw of LEDs, helping maintain the factory flash rate of 60–120 flashes per minute and preventing hyperflash. No external resistors or wiring are needed.
Heat buildup lowers LED efficiency. The integrated fan and metal heatsink system stabilizes temperature, maintaining consistent brightness and up to 10× longer lifespan.
The 1200-lumen output provides a significant brightness upgrade over halogen output (300-400 lumens), making the bulb easier to see in daylight and low-visibility conditions.
Installation is simple and plug-and-play. No cutting, splicing, or complicated wiring is required, and installation takes approximately 10 minutes.

Don’t forget to browse our 4257 LED bulbs collection or LED turn signal bulbs for additional fitments.

WHAT'S INCLUDED

BULBS :

2X 4257 Amber LEDs Bulbs With Built in Resistors

WARRANTY :

Includes a 1-Year Manufacturer Warranty covering defects under normal use.

PRODUCT INFORMATION

Function - Front Turn Signal / DRL

LED Chips - 54 SMD LEDs

Variant - 4257

Beam Angle - 360° Coverage

Color - Amber

Cooling System - Fan + Metal Heatsink

Electrical Design - CANBUS, Non-polar, CK Compatible

Voltage - 12V DC

Installation - Plug & Play

TECH SPECS

WATTAGE :

24W

LENGTH :

2.4"

DIAMETER :

0.83"

INTENSITY :

1200 Lumens

BLINKER CIRCUITS :

No Resistors Required

CIRCUITS :

12V

This product has a Includes a 1-Year Manufacturer Warranty covering defects under normal use.

Installation Video

Turn the vehicle off and let the bulb cool. Access the front turn-signal socket, remove the factory bulb, and install the new 4257 LED. Secure the socket and test the turn signal and DRL. This Underground Lighting bulb is plug-and-play, requires no wiring modifications, and takes approximately 10 minutes to install.

It depends on the F-150's year and headlight setup. Halogen-equipped models may use replaceable H11 or 9005 bulbs, while some trims have factory LED headlights.

The compatible front turn signal bulb is 4257, also cross-compatible with WT21 and 4257NA. Always check your factory bulb before ordering.

The Underground Lighting 4257 LED pair is listed at $64.99. The price is for two amber LED bulbs.

Fast blinking, or hyperflash, can happen when an LED has a lower electrical load than the factory bulb. This 4257 LED has a built-in resistor to help maintain the normal flash rate without an external resistor.

Compatible 2021 F-150 models use a 4257 front turn signal bulb. This Underground Lighting LED is a direct-fit 4257 replacement with a built-in resistor.

COMPATIBILITY

CROSS-COMPATIBILITY :

Wt21, 4257, 4257NA

FITMENTS :

2024 Ford F-150 – Front Turn Signal, 2023 Ford F150 STX – Front Turn Signal, 2023 Ford F-150 – Front Turn Signal, 2022 Ford F150 STX – Front Turn Signal, 2021 Ford F150 STX – Front Turn Signal, 2022 Ford F-150 – Front Turn Signal, 2021 Ford F-150 – Front Turn Signal, 2020 Ford F-150 – Front Turn Signal, 2020 Ford F-350 Super Duty – Front Turn Signal

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5 stars: 84 (97%)
4 stars: 2 (2%)
3 stars: 0 (0%)
2 stars: 0 (0%)
1 star: 1 (1%)

Some of the reviews shown are from related products the merchant grouped with this one.

Very bright.

Great lights

Really wish ford would have done all LED bulbs from the factory. Ordered a set of these front turn signal bulbs and wow, they are bright and work great. No error codes or hyper flashing. Seem very well made too. Took about 20 mins for install. Have a set of the brake/turn bulbs on the way next.

Completely satisfied with these bulbs! Amazing the difference between stock and these. Night and day! For the quality you can’t beat the price!

Dang!

Man these bulbs are way better than any other LEDs I have ever purchased! No hyper flashes, bright, beautiful! I feel sorry for who ever is in front of me when the blinkers are on!

Takes about 20 mins per side to install!

Great lights

I’m impressed with how bright these are!

took 13 days to get here for $6.56 and weighs a little more than a letter.

HI, You picked USPS ground which has no guaranteed time frame . We shipped your order the same day it was placed.
Sometimes USPS takes longer Which is not ideal. However, out of our control. If you were in a rush we offered better shipping options like FedEx ground, 2nd day and UPS options as well.

2021–2023 Ford F-150 STX LED Rear Turn Signal Replacement Bulbs for 3X Rear Visibility| 4257 Amber, Built-in Resistor, No Hyperflash | 300% Brighter 1200LM (PAIR)

2021-2023 Ford F150 STX Amber Rear Turn Signal LED Bulb W/ Built in Resistor No hyperflash (PAIR)

Look great easy to install

Awesome

Great service. Part was just what I needed.

Awesome lights

Very bright priced competitive

Work great

Easy install, no issues yet 👍

2023 F150 STX 4x4

These work great for the rear turn signals! Very bright. Will be ordering the reverse lights next. No hyper flash and no external resistors.

Exactly as described - works great

Purchased three sets of led lights for f150 - brake, front, rear turn signals. Units arrived quickly and exactly as described, well made, looks great. I would purchase again without hesitation.

10/10

Zero hyper flashing and significantly brighter than OEM turn signal lights. Would definitely buy again.

Ford f150 XLT

I'm very impressed with the light front and back very good quality lights i really love it thank you ⭐️⭐️⭐️⭐️⭐️

Excellent functionality, okay quality

The light bulb it self works and looks phenomenally, however this is the second set I have had to purchase in the past 2.5-3yrs. The LEDs will eventually die and cause the bulb to malfunction. The cause of the issue appears to be heat. I hope the ones I purchased this time last longer the last. But I am a return customer because the product is good and I haven’t found a competitor who offers the same plug and play design.

F150 STX LED LIGHT CONVERSION

AMAZING HOW BRIGHT THESE ARE AND SO EASY TO SWAP OUT THOSE DULL HALOGENS

Big improvement.

Easy to swap out forward halogen bulbs on the 2023 F 150 with the new Underground LED’s. Amazing difference in the brightness of these new amber directionals/parking lights. Big difference in daylight brightness.

Excellent plug & play upgrade

These lights are perfect! The construction is solid, and they even have a tiny fan that runs when they're turned on to keep them cool. Brilliant amber color as well. The headlamps look much more cohesive with all LEDs. Would highly recommend.

Super bright and no hyper flash.

These are great modification to make the signal lights are nice and bright now.

2023 F150 front turn signal

Super bright LEDs definitely worth the money very, very easy installation

Good Product

Lights perform exactly as described and installation was very easy.

Front turn signal bulbs

Easy plug and play, and super bright leds. I'm not sure why Ford doesn't include these with the led headlights in their 302a package... but they look great.

LED turn signals 22 f150

Works perfectly super fast shipping

Excellent product

I could tell immediately the lights were high quality. They were simple to install on my 2023 Ford F150 XLT. The LEDs may a huge difference in the amount of light be generated and not having to install resistors are absolutely worth the extra cost. Plug and Play. Great product!!

Absolutely love them

Love the LEDs. They are the perfect fit. They are very bright. And they were labeled for easy installation. Definitely recommend these guys

Easy install

Hyper flash

Bulbs are advertised as no hyper flash but will absolutely cause a random hyper flash. And yes all bulbs are pushed completely into the socket.
Vendor sent a different bulb and fixed the issue.
Great customer service.