The Oldsmobile Firenza brake light requires a 1157 bulb size for proper installation and function. Data for the specified component covers the period from 1982 through 1988.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Oldsmobile Firenza uses the 1157 bulb for its brake lights across all seven model years covered in the specifications, spanning 1982-1988.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output and a BAY15d bayonet base, conforming to ANSI standards for the US and Canadian markets.
The dual-filament design of the 1157 allows a single bulb to serve two functions, with the higher 21W filament handling the brake light and the lower 5W filament serving a secondary role such as a tail light.
The center high mount stop light (CHMSL) on the Firenza uses a different bulb than the standard brake lights, with the 1987-1988 models specifying the 2057 and the 1986 model specifying the 1156.
The 2057 is also a dual-filament bulb with a BAY15d bayonet base, operating at 12V with a 26.9W/8W output, making it a higher-wattage variant of the 1157.
Although the 1157 and 2057 share the same BAY15d bayonet base, the two bulbs are not identical, as the 2057 draws noticeably more wattage on both filaments.
The 1156 specified for the 1986 Firenza CHMSL is a single-filament bulb with a BA15s bayonet base, operating at 12V and 21W.
The BA15s base of the 1156 and the BAY15d base of the 1157 and 2057 are physically distinct, meaning these bulbs are not interchangeable despite their similar overall form.