Saturn LW200 brake bulb utilizes 3157 and P21/5W sizes, while the center high mount stop light bulb employs PC168 size. The replacement chart covers 2001 to 2003 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Saturn LW200 brake light circuit uses two distinct bulb standards across its model years. The 3157 follows the ANSI standard applicable in the US and Canada, while the P21/5W follows the ECE standard used in Europe and worldwide markets.
Both the 3157 and P21/5W are dual-filament bulbs operating at 12V, with the higher-intensity filament serving the brake function and the lower-intensity filament serving a secondary role such as running or tail light duty.
The 3157 is a T25 wedge-base bulb rated at 27W on its primary filament and 7W on its secondary filament. The P21/5W carries a BAY15d bayonet base and is rated at 21W and 5W respectively, reflecting a different wattage profile despite serving the same brake light function.
The BAY15d bayonet base of the P21/5W and the wedge base of the 3157 are physically incompatible socket types. The 2002 Saturn LW200 brake light housing accepts the P21/5W, while the 2001 and 2003 model years use the 3157, meaning these bulbs are not interchangeable across those years without socket modification.
The center high mount stop light on the Saturn LW200 uses the PC168 across the 2001-2003 model years, making it the only bulb position with a consistent specification throughout that entire production span covered in these records.
The PC168 is a T10 miniature wedge bulb operating at 12V and is designed specifically for printed circuit board twist-lock sockets. This socket type is distinct from standard wedge or bayonet fittings used in the brake lights, and the PC168 is not a substitute for either the 3157 or P21/5W in those positions.
The PC168 is classified under the ANSI standard and is noted in its description as intended for instrument clusters. Its presence in the center high mount stop light position of the LW200 reflects a design choice to route that circuit through a printed circuit board assembly rather than a conventional bulb socket.