Chevrolet Caprice Back Up Light Bulb Size

The Chevrolet Caprice back up light uses 921, 2057, 1156, and P21W bulb sizes depending on the specific version of the vehicle. Available data for the components covers the range from 1966 through 2017.

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
2011-2017	921
1991-1992	2057
1966-1990	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Brighter variant of 1157. 12V, 26.9W/8W.	2057
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Chevrolet Caprice back up light bulb specifications cover model years 1966-2017, with three distinct bulb types used across that span: the 1156, 2057, and 921.
The 1156 is the most widely used bulb type in these specifications, fitted to the Chevrolet Caprice from 1966-1990. It is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W.
The BA15s bayonet base on the 1156 is a single-contact design, meaning it is not interchangeable with dual-contact bayonet bases used on other bulb types in these specifications.
The 2057 bulb was specified for the 1991-1992 Caprice. It is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a dual wattage of 26.9W and 8W for its two filaments.
The BAY15d base on the 2057 is a dual-contact bayonet design. Although the 2057 is described as a brighter variant of the 1157, the 1157 and 2057 are not the same part and are not listed as interchangeable in these specifications.
The 921 is a wedge-type bulb in the T15 form factor, rated at 12V and 16W. It carries no bayonet base and is physically incompatible with the BA15s and BAY15d sockets used by the 1156 and 2057.
The 921 wedge bulb was specified for the Chevrolet Caprice from 2011-2017, reflecting a socket type that differs entirely from those used in earlier model years.
All three bulb types in these specifications conform to ANSI standards applicable in both the United States and Canada.
The wattage shift across the three bulb types is notable: the 1156 draws 21W, the 921 draws 16W, and the 2057 operates at 26.9W on its primary filament, making direct substitution across types inadvisable without confirming socket compatibility.
Because the 1156, 2057, and 921 each use a different base type, none of the three bulbs specified for the Caprice back up light position are cross-compatible with one another.