Saturn L300 front turn signal bulbs use 3457NA or 3457 size, while rear turn signal bulbs use 3157 or P21W size. The replacement chart covers 2001 through 2005 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Saturn L300 front turn signal uses the 3457NA bulb for the 2003-2005 model years and the 3457 bulb for the 2001-2002 model years.
The 3457NA is a dual-filament T25 wedge bulb rated at 12V and 27W/7W, distinguished by its natural amber glass envelope, which produces an amber output without relying on a colored lens or housing.
The 3457 shares the same T25 wedge form, 12V operating voltage, and 27W/7W dual-filament rating as the 3457NA, but its glass envelope is clear rather than amber-tinted.
Both the 3457NA and 3457 conform to the ANSI standard, the bulb classification system used in the United States and Canada.
The Saturn L300 rear turn signal uses the 3157 bulb for the 2003-2005 model years, which is also a dual-filament T25 wedge bulb rated at 12V and 27W/7W under the ANSI standard.
For the 2001-2002 model years, the Saturn L300 rear turn signal uses the P21W bulb, which follows the ECE standard used in Europe and worldwide markets rather than the ANSI standard.
The P21W is a single-filament bulb rated at 12V and 21W, and it uses a BA15s bayonet base, a mounting type that is physically incompatible with the wedge base found on the 3157, 3457, and 3457NA bulbs.
The shift from P21W to 3157 in the rear turn signal position between the 2002 and 2003 Saturn L300 represents a change in both the bulb standard and the base type, meaning these two bulbs are not interchangeable.
The 3457NA and 3457 share the same T25 wedge base and identical wattage ratings, but the amber glass coating on the 3457NA makes it application-specific in housings designed without an amber lens.
The 3157, 3457, and 3457NA all carry the same 27W/7W dual-filament output, meaning the higher-wattage filament serves the turn signal or brake function while the lower-wattage filament serves a secondary function such as parking or running light.