The Oldsmobile Starfire front and rear side marker bulb sizes are 194 and 194, 1157 respectively, with the 194 bulb size serving both positions. The replacement chart covers vehicle production years spanning 1975 to 1980 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 194 bulb follows the ANSI standard recognized in both the US and Canada. It is a miniature wedge type in the T10 form factor, rated at 12 volts and 3.78 watts.
The 1157 bulb also carries ANSI standardization for the US and Canada. It is a dual-filament bulb fitted with a BAY15d bayonet base, rated at 12 volts with a wattage split of 21W and 5W across its two filaments.
The dual-filament design of the 1157 means it serves two distinct lighting functions within a single housing, with the higher-wattage filament typically handling brighter signaling and the lower-wattage filament handling a reduced-intensity mode.
The T10 wedge base of the 194 and the BAY15d bayonet base of the 1157 are physically incompatible with each other, meaning the two bulb types are not interchangeable.
For the Oldsmobile Starfire, the front side marker position uses the 194 bulb across all model years covered in the specifications, spanning 1975-1980.
The rear side marker position on the Starfire uses the 194 bulb for 1975-1978 and 1980, while the 1979 model year uses the 1157 bulb instead.
The 1979 rear side marker fitment with the 1157 represents a departure from the otherwise consistent use of the 194 in that position, and the socket type in the 1979 rear housing would be specific to the BAY15d bayonet configuration rather than the wedge-style socket used in surrounding years.
Because the 1979 rear side marker socket is designed for the BAY15d bayonet base, substituting a 194 wedge bulb in that position would not be a compatible fitment.