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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

    • Talk to a REAL Human Expert

      Call us (561) 918-5225

    • 1-2 Year Warranty

      30 Day Quick Return

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