The Oldsmobile Regency front turn signal requires a 3357 bulb size while the rear turn signal uses a 2057 bulb size. The replacement chart covers 1997 to 1998 model 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 Regency uses two distinct bulb types across its front and rear turn signal positions for the 1997-1998 model years.
The front turn signal on the Oldsmobile Regency takes a 3357 bulb for both the 1997 and 1998 model years.
The 3357 is a single-filament wedge bulb in the T25 form factor, rated at 12V and 27W, and conforms to ANSI standards recognized in both the United States and Canada.
A single filament means the 3357 serves one lighting function only, which in this application is the turn signal.
The rear turn signal position uses a 2057 bulb across the same 1997-1998 model years.
The 2057 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a dual-wattage output of 26.9W and 8W, and also meets ANSI standards for the United States and Canada.
The dual-filament design of the 2057 allows it to serve two separate lighting functions from a single bulb, with the higher wattage filament handling the brighter turn signal function and the lower wattage filament handling a secondary function such as a running or parking light.
The 2057 is a brighter variant of the 1157 bulb, sharing the same BAY15d bayonet base, though the two are not directly interchangeable due to differences in wattage output.
The front and rear turn signal positions require different bulb types, meaning the 3357 and 2057 are not interchangeable with each other despite both operating at 12V with similar wattage ratings.
The wedge base of the 3357 and the BAY15d bayonet base of the 2057 represent physically incompatible mounting systems, which prevents accidental cross-installation between the two positions.