Saturn SW1 Back Up Light Bulb Size

The Saturn SW1 back up light requires bulb sizes 1156, P21W, and 3057 depending on the specific version of the vehicle. Available data for the bulb sizes covers the range from 1993 to 1999.

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
1996-1999	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 SW1 back up light specifications cover model years 1993-1999, split across two distinct bulb types depending on the production year.
The 1156 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W, conforming to ANSI standards recognized in both the US and Canada.
The BA15s bayonet base uses a single contact point at the base, which is a defining fitment characteristic of the 1156 and distinguishes it from visually similar bayonet-base bulbs with offset pins.
The Saturn SW1 (1996-1999) uses the 1156 bulb for the back up light position.
The 3057 is a dual-filament bulb in a T25 wedge form, rated at 12V with a 27W high filament and a 7W low filament, also conforming to ANSI standards for the US and Canada.
For the Saturn SW1 (1993-1995), the back up light position calls for the 3057 bulb.
The 1156 and 3057 are not interchangeable. Beyond their differing base types, one carries a single filament while the other carries two, and their wattage ratings differ as well.
The T25 wedge base of the 3057 is a friction-fit design that does not use a bayonet locking mechanism, making it physically incompatible with sockets designed for the BA15s base of the 1156.