2023 Ford F-350 Super Duty — Bulb Sizes (Headlight, Tail, Fog)

Quick reference

Note: Ford offered multiple exterior lighting packages on the 2023 Super Duty. Always confirm your truck’s equipment by visually inspecting the lamp housing for “LED” markings or part numbers, or by checking the build sheet.

LED vs halogen upgrade considerations

• CANBUS and hyper-flash: The F-350 monitors bulb load. Replacing 7444/3157/194/921 with low-draw LEDs can trigger outage warnings or rapid turn-signal flash. Use CANBUS-ready LEDs or add appropriate load resistors (generally 6–8 ohm, 25W) on each affected circuit.
• Headlights: If you have factory LED headlights, individual diodes aren’t serviceable—replace the assembly if it fails. If you have halogen H13 reflectors and want better output, a quality LED H13 upgrade can work, but choose units with correct focal positioning to avoid glare. Some trucks may require anti-flicker adapters.
• Fog lights: Many XLT+ trucks use sealed LED fog modules. On halogen fogs (H10/9145), LED replacements usually do not require resistors, but may need adapter collars. Aim fogs carefully to prevent scatter.
• Rear lamps: Higher trims with LED tails are module-based; you can often still upgrade just the 921 reverse (if equipped) to LED. On incandescent tails, 3157 LED upgrades for stop/turn require resistors to prevent hyper-flash.
• Interior: 194 and festoon upgrades are straightforward and error-free. Choose CANBUS-friendly 194s to avoid glow when doors are closed.

How to replace each bulb

• Headlight (H13 halogen): Turn wheels for access, remove the upper radiator cover fasteners, then pull the headlamp housing retaining pins. Slide housing forward, twist H13 counterclockwise to remove. Do not touch glass.
• LED headlamp assembly: Disconnect battery negative. Remove grille/top cover, pull retaining pins, unplug the multi-pin connector, and swap the assembly. Programming is not typically required.
• Fog light (H10/9145 halogen): From beneath the bumper, remove skid/air deflectors as needed. Twist the bulb a quarter turn. Avoid pulling on the wiring.
• DRL: On halogen setups, DRL uses the H13 high-beam filament—no separate bulb. LED DRL bars are integral to the headlamp.
• Front turn/parking (7444NA on halogen): Access at the headlamp rear. Twist the socket to remove and swap the amber bulb.
• Tail/brake/turn (3157 on incandescent): Lower the tailgate, remove two T-27/T-30 screws, pull the lamp straight back, twist the socket(s), and replace the 3157.
• Reverse (921): With the tail lamp removed, twist the reverse socket and install a 921. If upgrading to LED, test polarity before reassembly.
• License plate (194): Release the lens tab from below, twist the socket, and replace the 194.
• Side markers (194 on incandescent housings): Service with the respective headlamp/tail lamp removed; twist-out socket and replace.
• Interior map (194): Pry the lens gently with a trim tool, pull the wedge bulb. For LED, match polarity.
• Dome/cargo/CHMSL (578 festoon): Pry the lens, spring the contacts back, swap the festoon. Verify length (41–44 mm) before purchase.

Always disconnect the battery when working near airbag circuits or large harness connectors, and avoid prying painted surfaces.

Common lighting issues for this generation

• Moisture/condensation: Some trucks may show temporary condensation in headlamps or fogs after heavy rain/washing. Light misting that clears is considered normal; pooling or persistent fog indicates a vent or seal concern.
• Hyper-flash after LED swaps: Common when changing 7444/3157 to LED without resistors or CANBUS LEDs. Add resistors across the turn-signal positive and ground at each corner you’ve converted.
• Trailer-related turn signal faults: Corroded 7‑way connectors or trailer wiring can feed back into the BCM, causing warnings or fast flash. Isolate by unplugging the trailer and cleaning the socket.
• DRL behavior differences: Trucks configured for Canadian DRL may run different circuits than U.S. trucks. If an LED upgrade causes flicker only in DRL mode, add anti-flicker modules.
• Bed/cargo lamp failures: The CHMSL/cargo lamp unit can see water intrusion if the gasket is disturbed. Replace the gasket when servicing bulbs or the camera/CHMSL assembly.

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