2018 Ford F-250 Super Duty Bulb Size Guide

The 2018 Ford F-250 Super Duty is a powerhouse built for heavy towing and tough worksites. However, maintaining maximum visibility is crucial for safety, especially when you are hauling large loads at night. The 2018 model year features different lighting setups depending on your trim level. Lower trims like the XL and XLT typically come equipped with standard halogen reflector housings, while higher trims like the Lariat, King Ranch, and Platinum feature advanced factory LED lighting systems with sealed assemblies.

Below is your comprehensive guide to the bulb sizes and types used on the 2018 Ford F-250 Super Duty.

Quick reference

Note: If your F-250 is equipped with factory OEM LED headlights or taillights (common on Lariat and above, or as part of the BLIS system), those units are generally non-serviceable sealed assemblies. If a diode fails, the entire housing must be replaced.

LED vs halogen upgrade considerations

Upgrading a halogen-equipped F-250 to aftermarket LEDs is incredibly popular for improving nighttime visibility, but it comes with a few technical hurdles. The 2018 Super Duty utilizes a sensitive Body Control Module (BCM) that monitors electrical loads.

• CANBUS Errors and Flickering: Because aftermarket LEDs draw significantly less power than halogen H13 or 3157 bulbs, the BCM may think the bulb is burnt out. This can result in dashboard warning lights, headlight flickering, or the truck cutting power to the circuit entirely. You will likely need CANBUS decoders (anti-flicker harnesses) for your headlight and fog light upgrades.
• Hyperflashing: If you upgrade your turn signals to LED, they will flash rapidly (hyperflash). You can solve this by wiring in load resistors, or by using diagnostic software like FORScan to disable the bulb outage detection in the truck's computer.
• Housing Glare: H13 LED bulbs must have chips that perfectly mimic the halogen filament placement. Otherwise, the large reflector housings on the F-250 will scatter the light, blinding oncoming traffic without actually improving your down-road visibility.

How to replace each bulb

• Headlights (Low/High Beam & Front Turn): On the 2018 F-250, changing the headlight bulbs is notorious for being a bit labor-intensive. Ford designed the front end so that accessing the rear of the headlight housing requires removing the front grille and unbolting the headlight assembly. It takes a 10mm socket, a trim removal tool, and a bit of patience.
• Fog Lights: These are easily accessible from underneath the front bumper. Simply reach up behind the fog light housing, squeeze the tabs on the wiring connector, pull it off, and twist the 9140 bulb counterclockwise to remove it.
• Tail, Brake, and Reverse Lights: Drop the tailgate and locate the two 8mm bolts on the inner edge of the taillight housing. Remove them, pull the housing straight back to release the alignment pins, and twist the bulb sockets out. (Note: If you have BLIS blind-spot monitoring taillights, do not attempt to pry the housing open. It is a sealed LED unit).
• License Plate Lights: Reach behind the rear bumper, grasp the bulb socket, and twist it a quarter-turn counterclockwise to pull it out. The 194 bulb simply pulls straight out of the socket.
• Dome/Map Lights: Use a plastic trim tool to gently pop off the overhead console lenses. Be careful not to snap the brittle plastic tabs, especially in cold weather.

Common lighting issues for this generation

• BLIS Taillight Water Intrusion: A very common issue on the 2017-2019 Super Duty trucks equipped with the BLIS (Blind Spot Information System) LED taillights is water intrusion or micro-cracking. Water gets inside the sealed unit, which can cause the taillight to fail or even trigger a BLIS system fault on the dashboard.
• Headlight Connector Melting: In some halogen models, poor connections or running high-wattage aftermarket halogen bulbs can cause the H13 pigtail connector to melt. If your headlight goes out and the bulb is fine, inspect the plastic connector for heat damage.
• Condensation: Minor condensation in the large headlight housings is considered normal by Ford and should burn off when the lights are on. However, if water is pooling at the bottom of the lens, the housing seal has failed and the assembly needs replacement.

If you are dealing with persistent electrical gremlins, BCM faults, or need professional help installing an LED lighting conversion, do not risk damaging your truck's wiring. Find a trusted shop on Repairius.