The Oldsmobile Firenza front turn signal bulb size includes 2057NA, 1157NA, and 1034NA options, while rear turn signal applications use 1157 or 1156 bulb sizes. The replacement chart covers 1982 through 1988 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 Oldsmobile Firenza turn signal specifications reference five distinct bulb types across its 1982-1988 production span: 2057NA, 1157NA, 1034NA, 1157, and 1156.
Four of the five bulb types, specifically the 2057NA, 1157NA, 1034NA, and 1157, are dual-filament designs. A dual-filament bulb serves two lighting functions from a single housing, typically combining a brighter high-wattage filament for turn signaling with a dimmer low-wattage filament for running or parking light duty.
The 1156 is the only single-filament bulb in these specifications, rated at 12V and 21W. It uses a BA15s bayonet base, which is not interchangeable with the BAY15d base found on the dual-filament types, as the two base styles differ in pin alignment.
All five bulb types conform to ANSI standards applicable in both the United States and Canada, meaning they follow a shared North American specification for physical and electrical properties.
The 2057NA, 1157NA, 1034NA, and 1157 all share the BAY15d bayonet base. Despite this shared base type, wattage ratings differ across these bulbs, which is a relevant factor in fitment decisions.
The 2057NA is rated at 12V with filaments drawing 26.9W and 8W respectively, making its high-beam filament noticeably brighter than the 21W high filament found in the 1157NA and 1034NA.
The "NA" suffix on the 2057NA, 1157NA, and 1034NA designates natural amber glass, meaning the amber color is produced by the glass itself rather than by a coating or lens filter.
The 1034NA is described as a variant of the 1157 and shares the same 12V, 21W/5W rating as the 1157NA, though it carries a different ANSI designation. The 1034NA and 1157NA are not confirmed as interchangeable within these specifications despite their matching wattage values.
The Oldsmobile Firenza (1982-1984) front turn signal uses the 1034NA, while the 1985 model returns to the 1157NA before the 1986 model reverts to the 1034NA again, and the 1987 model uses the 1157NA once more. The 1988 model front position specifies the higher-output 2057NA.
The rear turn signal position on the Oldsmobile Firenza uses the 1157 for 1983-1988 model years, while the 1982 model uses the 1156. Because the 1156 has a BA15s single-pin base and the 1157 has a BAY15d dual-offset-pin base, these two bulbs are not physically interchangeable.