Oldsmobile Starfire Back Up Light Bulb Size

The Oldsmobile Starfire back up light utilizes 1073, 1156, and P21W bulb sizes depending on the specific production period for the vehicle. Available data covers the range from 1954 through 1980.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1975-1980	1156
1964-1966	1156
1963	1073
1961-1962	1156
1954-1957	1073

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 13W.	1073

Other Locations

Additional Notes

The Oldsmobile Starfire uses two bulb types across its model years for the back up light: the 1156 and the 1073, both of which are ANSI-standardized single-filament bulbs rated at 12 volts and fitted with a BA15s bayonet base.
The 1156 bulb is rated at 21 watts, while the 1073 is rated at 13 watts, making the two types electrically incompatible as direct substitutes despite sharing the same BA15s base style.
The BA15s bayonet base is a single-contact design, which distinguishes it from the dual-contact BA15d base used in two-filament applications. This single-contact configuration is consistent with a back up light function, which requires only one filament.
The 1156 bulb is specified for the Oldsmobile Starfire across 1961-1966 and 1975-1980, representing the majority of model years in the data.
The 1073 bulb is specified for the 1954-1957 and 1963 model years of the Starfire.
The 1963 model year is a notable fitment exception within the mid-1960s production run, as it calls for the lower-wattage 1073 rather than the 1156 used in the surrounding years.
Because the 1073 and 1156 share the same BA15s bayonet base, physical installation of either bulb into the other's socket is possible, making wattage verification an important step before installation.
Installing a 1156 in place of a specified 1073 would introduce a higher current draw than the original circuit was designed for, as the wattage difference between the two types is 8 watts.