The Buick GS 350 front turn signal requires 1157NA or 1034NA bulb sizes, while the rear turn signal uses a 1157 bulb size. The replacement chart covers 1968 to 1969 production 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 1157NA, 1034NA, and 1157 bulbs specified for the Buick GS 350 are all dual-filament types, meaning each bulb serves two functions within a single housing, typically combining turn signal and parking light operation through separate filaments rated at 21W and 5W respectively.
All three bulb types share the BAY15d bayonet base, a two-pin offset base design that physically locks the bulb into the socket with a twist. The offset pin placement prevents incorrect insertion orientation.
The 1157NA and 1034NA variants carry an "NA" suffix denoting natural amber glass, which produces an amber-colored output without relying on an amber-tinted lens. The standard 1157 uses clear glass and depends on the vehicle's lens for any color filtering.
The 1034NA is noted as a variant of the 1157, sharing the same BAY15d base and 12V, 21W/5W electrical ratings, though the two carry distinct ANSI designations and are not listed as interchangeable within these specifications.
The front turn signal of the Buick GS 350 changed bulb types between model years, with the 1968 model using the 1034NA and the 1969 model using the 1157NA, making year-specific fitment a relevant factor for front positions.
The rear turn signal position used the 1157 bulb in both 1968 and 1969, indicating no change in rear bulb specification across those two model years.
Because the 1157NA and 1157 share the same base type and wattage ratings, the physical and electrical construction is closely related, but the amber glass coating of the 1157NA distinguishes it as a separate part number from the clear 1157.
All bulbs in these specifications conform to ANSI standards applicable in both the United States and Canada, reflecting a standardized classification system used to define electrical and physical bulb characteristics across the North American market.