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Underground Lighting  |  SKU: F150-Rear-21

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

$69.99

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Rear signals too dim in traffic while changing lanes?

  • 300% brighter than halogen for clearer braking and 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 4257 LED Brake Bulb Beats Everything Else

- Brake lights compete with sunlight, rain, and surrounding vehicles. Halogen bulbs output ~300–400 lumens, limiting visibility, whereas 1600-lumen LED output improves detection distance, helping following drivers react faster.

- Direct Fit for 2021–2025 Ford F-150 truck models, go to compatibility for exact fitment or use our vehicle search tool to verify fit.

- 12 high-power LEDs produce 1600 lumens across a 360° beam angle, ensuring visibility from rear and side angles. This improves braking awareness, lane-change signalling, and collision prevention.

- Dual-intensity 4257 design supports brake, turn, and parking functions, switching between low and high output instantly ensuring clear signal separation and faster driver recognition.

- LED bulbs draw lower current than halogen bulbs, triggering rapid blinking. Built-in resistor simulates factory load (~60–120 flashes/min), restoring correct flash rate without external resistors.

- Excess heat reduces LED efficiency and lifespan. The fan + metal heatsink system regulates temperature, maintaining stable brightness output and extending lifespan up to 10× longer than halogen bulbs.

- Designed in the USA and built with Japanese components, ensuring durability and precision. Improved thermal and electrical stability delivers consistent 1600-lumen output and long-term reliability.

- 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 :
    2× 4257 Red CANBUS LED Bulbs with Built in Resistor
    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

    WATTAGE :
    27W
    LENGTH :
    2.4"
    DIAMETER :
    .83"
    INTENSITY :
    1600 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

    Installation Video

    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.

    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.

    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.

    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.

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

    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.

    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

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

    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

    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

    • Talk to a REAL Human Expert

      Call us (561) 918-5225

    • 1-2 Year Warranty

      30 Day Quick Return

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