Ford Crown Victoria Back Up Light Bulb Size

Additional Notes

• The Ford Crown Victoria backup light bulb specifications span the 1992-2011 model years, with four distinct ANSI-standard bulb types used across that range: the 921, 2356, 2456, and 3156.
• The 921 is a single-filament wedge bulb in a T15 form factor, rated at 12V and 16W. It is the specified backup light bulb for the Crown Victoria from 1992-1996 and again in 1997, making it the bulb type used across the longest uninterrupted stretch of model years in these specifications.
• The 3156 is a single-filament wedge bulb in a larger T25 form factor, rated at 12V and 27W. It is specified for the 1998 and 2001 model years.
• The T25 form factor of the 3156 is physically larger than the T15 of the 921, meaning these two wedge bulb types are not interchangeable despite sharing a wedge base style.
• The 2356 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V. Its dual-filament design distinguishes it from the single-filament 921 and 3156 types also found in these specifications.
• The 2456 is a festoon-style bulb rated at 12V, classified as a specialty application type under the ANSI standard. Festoon bulbs use a cylindrical form factor with end-cap contacts rather than a wedge or bayonet base.
• The 2356 and 2456 share the same 12V operating voltage but differ in base type and filament count, making them non-interchangeable despite their similar part number designations.
• All four bulb types in these specifications conform to ANSI standards recognized in both the United States and Canada.
• The 2456 is the most frequently specified bulb across the Crown Victoria's model year range, appearing in 2000, 2002-2003, 2005-2006, and 2010-2011.
• The backup light bulb specification for the Ford Crown Victoria changed multiple times across consecutive model years, such as between 2003 (2456) and 2004 (2356), indicating that the same base vehicle platform did not necessarily retain the same bulb fitment year over year.