2025 Ford F-350 Super Duty Bulb Sizes (Headlight, Tail, Fog)

As an ASE-certified master technician, I’ve worked on countless heavy-duty trucks, and the 2025 Ford F-350 Super Duty is a frequent visitor in the shop for upfitting and maintenance. Ford's 2023+ generation of the Super Duty features a robust electrical architecture, and understanding your specific trim level is critical when it comes to lighting. Lower trims like the XL and XLT typically come with standard halogen housings, while the Lariat, King Ranch, Platinum, and Limited trims boast advanced, non-serviceable factory LED projector setups.

If you are looking to replace a burnt-out bulb or upgrade your base-model F-350's lighting, use this comprehensive bulb size guide to get the right parts the first time.

Quick reference

Note: Trims with factory LED packages (Lariat and above, or XLT Premium packages) use integrated LED assemblies for headlights, taillights, and fog lights. These assemblies do not have replaceable bulbs; the entire unit must be replaced if it fails.

LED vs halogen upgrade considerations

Upgrading your halogen XL or XLT F-350 to aftermarket LEDs is a popular modification, but it requires careful attention to Ford's sensitive Body Control Module (BCM).

• CANBUS Errors and Hyper-Flashing: The 2025 Super Duty employs a strict CANBUS system. If you install aftermarket LED turn signals or headlights, the truck will likely detect the lower power draw and trigger a "bulb out" warning on the dash, followed by hyper-flashing. You will need LED bulbs with built-in CANBUS decoders, or you must install external load resistors. Alternatively, tools like FORScan can be used to disable the bulb-out outage detection in the BCM.
• Headlight Clearances: Heavy-duty cooling fans on high-lumen aftermarket H13 LED bulbs can sometimes interfere with the rear dust caps on the headlight housings. Ensure you purchase a low-profile LED kit or extended dust caps to maintain a watertight seal.
• Beam Pattern: Always use an LED bulb designed to mimic the halogen filament placement. Slapping cheap LEDs into the massive reflector housings of the F-350 will scatter light, blinding oncoming traffic and reducing your actual road visibility.

How to replace each bulb

• Headlights (Low/High Beam): Ford has made accessing the headlight bulbs on the newer Super Duty generation a bit tighter. Going through the wheel well by removing the front fender liner clips often provides the best access to the rear of the headlight assembly without having to pull the front grille.
• Fog Lights: These are easily accessible from underneath the front bumper. Just reach up behind the bumper corner, squeeze the locking tabs on the connector, and twist the bulb counter-clockwise to remove.
• Tail Lights (Brake/Turn/Reverse): Lower the tailgate and remove the two 8mm bolts on the inside lip of the bed. Pull the taillight assembly straight back toward you (do not pry outward, or you'll snap the plastic alignment pins). Twist the sockets out to swap the 3157 or 921 bulbs.
• License Plate / Cargo / 3rd Brake: The 3rd brake light is held by four screws on the back of the cab. Be careful not to overtighten them upon reinstallation, as the plastic housing cracks easily. License plate bulbs are accessed from under the rear bumper by twisting the socket out.
• Interior Dome/Map: Use a plastic non-marring trim tool to gently pop off the overhead console lenses.

Common lighting issues for this generation

While the 2025 F-350 is relatively new, it shares its electrical architecture with the 2023+ models. A few common issues have emerged:

1. Cab Light Leaks: If your truck has factory roof clearance lights, the seals can sometimes degrade or be installed improperly at the factory, leading to water dripping down the A-pillar or headliner.
2. Tailgate Wiring Harness: On trucks subjected to heavy off-road or construction use, the wiring harness at the tailgate hinge (which supplies power to the license plate lights and backup camera) can chafe.
3. Condensation in LED Housings: A small amount of condensation in the factory LED projector housings is considered normal by Ford, provided it burns off after 30 minutes of the lights running. If water begins to pool, the housing must be replaced.

If you are dealing with complex BCM faults, need a professional upfitter for auxiliary lighting, or want to properly aim your new headlights, don't leave it to chance. Find a trusted shop on Repairius.