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Underground Lighting  |  SKU: 4257-F150R-A

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)

$64.99 $69.99

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Weak rear visibility in traffic? 

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

Why This Rear Turn Signal Bulb Beats Everything Else

  • - Rear signals must cut through glare, rain, and brake light interference. Halogen bulbs output ~300–400 lumens, limiting detection distance. 1200-lumen LED output improves contrast and visibility, helping following drivers react faster.

  • - 54 SMD LEDs deliver 1200 lumens with full 360° distribution, ensuring visibility from rear and side angles. This improves lane-change signaling, braking awareness, and intersection safety, where angle visibility is critical.

  • - LED bulbs draw lower current than halogen bulbs, triggering rapid blinking. Integrated resistor matches factory load (~60–120 flashes/min), restoring correct blink rate while controlling heat through optimised circuit design.

  • - Excess heat reduces LED efficiency and lifespan. The fan + metal heatsink system regulates temperature, maintaining stable brightness output and extending operational life up to 15X to 50X longer than halogen bulbs.

  • - 4257 direct-fit base with non-polar CANBUS design integrates with 12V vehicle systems. No wiring, no external resistors, no modifications—ensuring fast installation and consistent electrical performance.

  • - Designed in the USA and built with Japanese components, ensuring tighter tolerances and durability. Improved thermal control and electrical stability deliver consistent 1200-lumen output and longer service life.

  • Efficient LED Upgrade Over Halogen Consumes 90% less power while delivering brighter, instant illumination compared to incandescent bulbs.

  • - Legal mandate in many states for rear turn signal lights sets the color standard at amber. This crisp, bright and reliable color option is the best for Ford.

  • - Installation time is approximately 10 minutes. There is no need for slicing or complicated wiring. This light is a plug-and-play installation and operation. 

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! 

Also, check our full collection of Turn signal bulb.

 

    WHAT'S INCLUDED

    BULBS :
    2X Amber Leds With Built in Resistors
    WARRANTY :
    Includes a 1-Year Manufacturer Warranty covering defects under normal use.

    PRODUCT INFORMATION

    Function - Rear Turn Signal

    Bulb Size - 4257

    LED Chips - 54 SMD LEDs

    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 :
    .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.
    📄 Download Installation & Tutorial PDF

    In North America, amber turn signals are the legal standard for all vehicles. Other drivers recognise amber signals more quickly, and reaction time is reduced by up to 0.3 seconds. Our LEDs automatically handle this requirement, displaying the correct color at the right time. When you're finding a new bulb, you won't need to choose between white or amber LED switchback turn signal lights - the dual-function technology does this for you. 

    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.

    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

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

    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.

    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

    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

    COMPATIBILITY

    FITMENTS :
    2023 Ford F150 STX – Rear Turn Signal, 2023 Ford F-150 – Rear Turn Signal, 2022 Ford F150 STX – Rear Turn Signal, 2021 Ford F150 STX – Rear Turn Signal, 2022 Ford F-150 – Rear Turn Signal, 2021 Ford F-150 – Rear Turn Signal
    • 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.
    B
    Bruce M

    Very bright.

    J
    Jason Bourgeois
    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.

    K
    Kevin Domer

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

    C
    Chase Shoemake
    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!

    N
    Nick Wrobleski
    Great lights

    I’m impressed with how bright these are!

    m
    michael

    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.

    L
    Lonnie Toews

    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)

    J
    Jaime Lopez

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

    M
    Michael

    Look great easy to install

    L
    Larry Davis
    Awesome

    Great service. Part was just what I needed.

    T
    Todd Holland
    Awesome lights

    Very bright priced competitive

    K
    Kaden Johnson
    Work great

    Easy install, no issues yet 👍

    R
    Ram H
    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.

    P
    Peter B
    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.

    J
    John Pino
    10/10

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

    E
    Edwin Calcano
    Ford f150 XLT

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

    B
    Bob
    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.

    T
    Thomas
    F150 STX LED LIGHT CONVERSION

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

    T
    Tim
    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.

    M
    Matt Hines
    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.

    J
    Joseph Morea
    Super bright and no hyper flash.

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

    B
    Brad Goettl
    2023 F150 front turn signal

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

    A
    Anthony Hobert
    Good Product

    Lights perform exactly as described and installation was very easy.

    J
    John Ritz
    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.

    D
    David Glazer
    LED turn signals 22 f150

    Works perfectly super fast shipping

    M
    Michael
    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!!

    g
    gilberto jaquez
    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

    I
    Ian Scribner

    Easy install

    S
    Steven Franklin
    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.

    • Talk to a REAL Human Expert

      Call us (561) 918-5225

    • 1-2 Year Warranty

      30 Day Quick Return

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      On orders over $89.99

    • Ships Same Day

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