Saturn SC2 Back Up Light Bulb Size

The Saturn SC2 back up light utilizes 921, 1156, and P21W bulb sizes depending on the specific version of the vehicle. Available information covers the range from 1993 through 2002.

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
2001-2002	921
1993-2000	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Saturn SC2 backup light specifications cover model years 1993-2002 and reference two distinct bulb types: the 921 and the 1156.
The 1156 is an ANSI-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base. The bayonet base uses a push-and-twist locking mechanism, which differs from the wedge-style retention used in other bulb families.
The 921 is an ANSI-standard wedge bulb in the T15 form factor, rated at 12V and 16W. Wedge bulbs rely on spring-loaded contacts gripping the base directly, with no separate socket pins or bayonet lugs.
The Saturn SC2 (1993-2000) uses the 1156 bulb for the backup light position, while the 2001-2002 model years use the 921 instead.
Because the 1156 uses a BA15s bayonet base and the 921 uses a wedge base, the two bulb types are not physically interchangeable despite both operating at 12V.
The wattage difference between the two types is notable: the 1156 draws 21W while the 921 draws 16W. Installing a bulb of the wrong wattage rating in a socket designed for the other type could affect circuit load, though the physical incompatibility of the bases makes accidental substitution unlikely.
Both the 921 and 1156 conform to ANSI standards applicable in the United States and Canada, meaning their electrical and physical specifications are governed by a common North American standardization framework.