Oldsmobile Jetstar I front and rear turn signal bulbs use a 1157 size. The replacement chart covers 1964 to 1965 production years with bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1157 is the sole bulb type specified for the Oldsmobile Jetstar I across all listed turn signal positions and model years.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single envelope, allowing it to serve two distinct lighting functions from one unit.
It operates on a BAY15d bayonet base, a two-pin offset base design that prevents incorrect insertion by positioning the two pins at different heights along the base.
The 1157 carries a 12-volt rating, consistent with the standard electrical system voltage found in passenger vehicles of that era.
Its dual wattage rating of 21W/5W corresponds to its two filaments, with the higher-wattage filament serving the active turn signal function and the lower-wattage filament serving a secondary role such as parking or running light duty.
The 1157 conforms to ANSI standards and holds recognition in both the United States and Canada, indicating a standardized specification shared across North American markets.
The Jetstar I used the 1157 in both the front and rear turn signal positions for the 1964-1965 model years, making it a uniform fitment across all four turn signal sockets on the vehicle.
Because the same bulb number appears in both the front and rear positions, the sockets at all four locations are electrically and physically compatible with the same replacement unit.