Ford F-150 Brake Bulb Size

Additional Notes

• The 4057 bulb is the most frequently specified brake bulb size across the Ford F-150 model range covered in these specifications, appearing across the 2005-2014 model years. Like the 3157, it is a dual-filament T25 wedge bulb rated at 12V with a 27W/7W output, making the two types electrically equivalent despite carrying different ANSI designations.
• The 3157 and 4057 share identical voltage and wattage ratings (12V, 27W/7W) and the same T25 wedge form factor, yet they carry distinct ANSI part numbers. These two types are not automatically interchangeable, as physical or keying differences between ANSI-designated bulbs can affect fitment even when electrical ratings match.
• The Ford F-150 (2015-2020) specifies the 3157 brake bulb only for vehicles equipped with Halogen Capsule Headlamps, indicating that headlamp configuration is a determining factor in brake bulb selection for those model years.
• The WT21/7W is designated as a Ford OEM part rather than an ANSI-standard bulb. It is a dual-filament T20 wedge type rated at 12V, 21W/7W, and its lower wattage output on both filaments distinguishes it from the T25-based 3157 and 4057 types used in earlier model years.
• The 2021-2022 model years specify the WT21/7W without any headlamp configuration qualifier, whereas the 2015-2020 entries for the 3157 carry the "With Halogen Capsule Headlamps" condition. This reflects a change in how brake bulb fitment is defined across those generations.
• The 1157 bulb, specified for the 1975-1987 model years, differs structurally from all other brake bulb types in these specifications. It uses a BAY15d bayonet base rather than a wedge base, and its dual-filament output is rated at 12V, 21W/5W, placing it at a lower wattage than the T25 wedge types that followed in later model years.
• The 912 is the most frequently specified Center High Mount Stop Light bulb across these entries, covering the 1997-1998 and 2009-2022 model years. It is a T15 wedge bulb rated at 12V and 12W, and it is described as a variant of the 921.
• The 921 and 922 are both T15 wedge bulbs sharing the same 12V, 16W rating, yet they are listed as separate ANSI designations. The 921 is specified for the 1994 and 2004-2008 Center High Mount Stop Light positions, while the 922 appears only for 1995-1996, indicating that year-specific fitment distinctions exist between these otherwise similarly rated types.
• The 912 is rated at 12W, whereas the 921 and 922 are each rated at 16W. All three share the T15 wedge form factor, but the wattage difference means the 912 is not a direct electrical substitute for the 921 or 922 despite their physical similarity.
• The WT21/7W is noted in its description as originally used across the Ford F-150, Bronco, and Maverick, establishing it as a shared OEM component across multiple Ford platforms rather than a part exclusive to the F-150.