Saturn L300 Back Up Light Bulb Size

The Saturn L300 back up light utilizes 921 and P21W bulb sizes for the rear illumination system. Data for the specified components covers the period from 2001 through 2005.

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
2003-2005	921
2001-2002	P21W

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The Saturn L300 uses two distinct bulb types across its model years: the 921 for 2003-2005 and the P21W for 2001-2002.
The 921 is an ANSI-standard bulb, meaning it follows North American specifications used in the United States and Canada.
The 921 uses a wedge-style base in a T15 envelope, operating at 12 volts and 16 watts.
The P21W follows the ECE standard, a regulatory framework applied across Europe and much of the rest of the world.
The P21W uses a BA15s bayonet base, a single-contact fitting that differs mechanically from the wedge base of the 921.
The P21W operates at 12 volts and 21 watts, making it 5 watts higher in power output than the 921 used in later model years.
The 921 and P21W are not interchangeable. Their base types are physically incompatible, and their wattage ratings differ.
The shift from the P21W to the 921 between the 2002 and 2003 Saturn L300 represents a change from a European-standard bayonet bulb to a North American-standard wedge bulb.