Ford Pinto Back Up Light Bulb Size

The Ford Pinto back up light uses bulb size 1156 and P21W for illumination. Data for the specified components covers the range from 1971 to 1980.

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
1971-1980	1156

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

The Ford Pinto uses the 1156 bulb for the back up light across all model years from 1971 to 1980.
The 1156 is a single-filament bulb, meaning it serves one lighting function rather than combining two, such as stop and tail, into a single unit.
The 1156 operates at 12 volts and 21 watts, which is consistent with standard automotive electrical systems of that era.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a single-contact bayonet fitting with a 15mm base width.
The 1156 conforms to ANSI standards and is recognized in both the United States and Canada, reflecting a standardized specification shared across North American markets.
Because the 1156 is a single-filament type, it is not interchangeable with the 1157, which shares the same BA15d bayonet base style but carries a dual-filament design and a second contact pin.