The Buick GS front side marker bulb size includes 194, 97, and 194NA options, while the rear side marker bulb size includes 194 and 1157 options. The replacement chart covers 1970 to 1972 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 194 bulb is the most frequently specified type across the Buick GS side marker positions, appearing in both the front and rear locations for the 1972 model year and in the rear for 1970.
The 194 is a T10 miniature wedge bulb rated at 12V and 3.78W, conforming to ANSI standards for the US and Canadian markets.
The 194NA specified for the 1970 Buick GS front side marker shares the same T10 wedge form factor and 12V, 3.78W electrical rating as the standard 194, but features natural amber glass rather than a clear envelope.
Because the 194NA and 194 are electrically and physically identical aside from glass color, substituting a clear 194 in the 1970 front position would alter the emitted light color.
The 1157 bulb specified for the 1971 rear side marker is a dual-filament type with a BAY15d bayonet base, rated at 12V with filaments drawing 21W and 5W respectively.
The BAY15d base of the 1157 uses offset locating pins to prevent incorrect insertion, distinguishing it physically from single-filament bayonet types.
The 97 bulb specified for the 1971 Buick GS front side marker is a single-filament BA15s bayonet base bulb rated at 12V and 13W, classified as a variant of the 1156 family.
The BA15s base of the 97 uses a single center pin, making it physically incompatible with the dual-offset-pin BAY15d socket used by the 1157 rear bulb of the same model year.
The 1971 model year is the only year in these specifications where the front and rear side marker positions use bulbs from entirely different base families, the BA15s for the front and the BAY15d for the rear.
All four bulb types listed conform to ANSI standards applicable to both the United States and Canadian markets.