Saturn SW2 Back Up Light Bulb Size

The Saturn SW2 back up light utilizes bulb sizes 1156, 3057, and P21W depending on the specific version of the vehicle. Data for the lighting components covers the range from 1993 to 2001.

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
1996-2001	1156
1993-1995	3057

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3057

Other Locations

Additional Notes

The Saturn SW2 back up light specifications cover model years 1993 through 2001, split across two distinct bulb types.
The 1156 bulb is an ANSI-standard single-filament type rated at 12V and 21W, fitted with a BA15s bayonet base, and is the specified back up light bulb for the Saturn SW2 from 1996 through 2001.
The BA15s bayonet base uses a single contact pin, which physically prevents installation of dual-contact bayonet bulbs in the same socket.
The 3057 is an ANSI-standard dual-filament bulb in a T25 wedge form, rated at 12V with a high filament of 27W and a low filament of 7W, and is the specified back up light bulb for the SW2 from 1993 through 1995.
Because the 1156 uses a bayonet base and the 3057 uses a wedge base, the two bulb types are not interchangeable with each other.
Both the 1156 and the 3057 conform to ANSI standards recognized in both the United States and Canada.
Although the 3057 carries a dual-filament design, its application in the SW2 back up light position means only the circuit relevant to that function is engaged.
The wattage difference between the two bulbs is notable: the 1156 draws 21W as a single-filament unit, while the 3057 draws up to 27W on its high filament, reflecting a higher output ceiling in the earlier SW2 specification.