Ford E-250 Back Up Light Bulb Size

Additional Notes

• The Ford E-250 back up light specifications span model years 1975 through 2014, with three distinct bulb types appearing across that range: the 1156, 2456, 2356, and 3156.
• The 1156 bulb is a single-filament type with a BA15s bayonet base, rated at 12V and 21W under the ANSI standard applicable in the US and Canada. It is the sole bulb specified for the Ford E-250 from 1975 through 1991.
• The 2456 is a festoon-style bulb designated for specialty applications, operating at 12V under the same ANSI standard. It is the most frequently specified bulb across the full range, appearing in 1992 and recurring across multiple subsequent model years through 2013.
• The 3156 is a single-filament wedge bulb in a T25 form factor, rated at 12V and 27W. It first appears in the 1993 model year and recurs at irregular intervals through 2011.
• The 2356 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V. Its BAY15d base differs physically from the BA15s base of the 1156, making the two types non-interchangeable despite their similar bayonet-style mounting.
• The BAY15d base of the 2356 features two pins offset at different heights, which mechanically prevents incorrect installation in a socket designed for a single-height BA15s base. This distinction is relevant for the Ford E-250 given that both base types appear across its model year range.
• The 3156 wedge base and the bayonet bases of the 1156 and 2356 are physically incompatible with one another, meaning socket type is a determining factor when selecting a replacement for any given model year of the Ford E-250.
• The 2014 Ford E-250 uses the 2356, a dual-filament bulb, for the back up light position, which is a functional departure from the single-filament 3156 specified for the 2011 model year.
• All four bulb types in these specifications conform to ANSI standards recognized in both the US and Canada, indicating consistent regulatory compliance across the entire model year range covered.
• The back up light bulb specification for the Ford E-250 changed multiple times between 1992 and 2014, with no single bulb type remaining constant across consecutive model years throughout that period.