Ford F-350 Back Up Light Bulb Size

The Ford F-350 back up light utilizes 1156, 199, 2356, 2456, 3156, and P21W bulb sizes for the rear illumination system. Available data for the specified components covers the range from 1969 through 1997.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1997	2456
1995-1996	3156
1994	2356
1992-1993	1156
1990-1991	2456
1989	3156
1971-1988	1156
1969-1970	199

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Festoon bulb, specialty application. 12V.	2456
ANSI standard (US & Canada). Single-filament wedge bulb (T25). 12V, 27W.	3156
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V.	2356
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Variant of 1156. 12V, 21W.	199

Other Locations

Additional Notes

The Ford F-350 backup light specifications span model years 1969 through 1997, covering a range of five distinct ANSI-standard bulb types across that period.
The 1156 bulb is the most frequently specified backup light bulb for the Ford F-350, covering model years 1971-1988 and 1992-1993. It is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W.
The bulb numbered 199 shares the same BA15s bayonet base, single-filament design, and 12V/21W rating as the 1156, and is classified as a variant of it. It is specified for the 1969-1970 model years.
Because the 199 and 1156 bulbs share the same base type and electrical ratings, their physical and electrical compatibility is closely related, though substitution should be confirmed against fitment requirements before use.
The 3156 is a single-filament wedge bulb of the T25 type, rated at 12V and 27W. It is specified for the Ford F-350 in 1989 and again in 1995-1996, making it the highest wattage bulb among those listed in these specifications.
The 2456 is a festoon-style bulb rated at 12V and is designated for specialty applications under the ANSI standard. It is specified for the F-350 in 1990-1991 and again in 1997.
The 2356 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V. It is the only dual-filament bulb in these specifications and is listed solely for the 1994 model year.
The BAY15d base of the 2356 is physically distinct from the BA15s base used by the 1156 and 199 bulbs. The two base types are not interchangeable, as the BAY15d includes offset pins to prevent incorrect installation of a single-filament bulb in a dual-filament socket.
The wedge base of the 3156 differs structurally from the bayonet bases used by the 1156, 199, and 2356 bulbs, and from the festoon format of the 2456, meaning none of these five bulb types are directly interchangeable with one another.
The F-350 backup light specification changed bulb type multiple times across the years covered, with at least five distinct transitions occurring between 1969 and 1997.