2021 Ford F-250 Super Duty Bulb Sizes and Replacement Guide

Quick Reference

This guide provides comprehensive information on bulb sizes for the 2021 Ford F-250 Super Duty. It's important to note that many F-250 models, especially higher trim levels like the Lariat, King Ranch, and Platinum, came equipped with factory LED headlights, tail lights, and fog lights. For these vehicles, individual bulb replacement is generally not possible as the LEDs are integrated into the housing. This guide primarily focuses on the halogen bulb equivalents found on lower trim models or as options on others.

For vehicles with factory LED headlights, the low beam, high beam, and sometimes the DRL and fog lights are sealed LED units. If there's a malfunction with these, the entire assembly typically needs to be replaced. Always check your specific vehicle's trim level and current bulb type before purchasing replacements or upgrades.

Headlights

On F-250s equipped with halogen headlights, the low beam utilizes an H11 bulb, and the high beam uses a 9005 bulb. These are separate bulbs within the same headlight assembly. Halogen DRLs commonly use the same 4257 or 3157 bulb found in the front turn signals.

Fog Lights

Halogen fog lights typically use an H10 (also known as 9145) bulb.

Turn Signals and Brake Lights

The front turn signals often double as the DRL and use a 4257 or 3157 dual-filament bulb. The rear turn signals, brake lights, and tail lights universally use a 3157 dual-filament bulb. It's crucial to ensure you're using a dual-filament bulb for these applications where both functions are present.

Reverse Lights

The reverse lights commonly use a 921 bulb, providing bright illumination for backing up.

License Plate Lights

To illuminate your rear license plate, the F-250 uses 168 bulbs.

Side Marker Lights

Both front and rear side marker lights generally utilize a 194 bulb.

Interior Lighting

For interior illumination, the front dome light often uses a 578 festoon-style bulb, while the map lights typically use 194 wedge bulbs.

LED vs Halogen Upgrade Considerations

Upgrading from halogen to LED bulbs can significantly enhance visibility and modernize the look of your 2021 F-250 Super Duty. However, there are several key considerations:

• CANBUS Errors: Modern vehicles like the F-250 utilize a CANBUS (Controller Area Network Bus) system that monitors electrical circuits. LED bulbs draw significantly less power than halogens, which can trigger