Buick Special Back Up Light Bulb Size

The Buick Special back up light uses 1156, 1073, and P21W bulb sizes depending on the specific version of the vehicle. Data for the components covers the range from 1954 through 1969.

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
1961-1969	1156
1954-1958	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 Buick Special uses two bulb types across its model years for the back up light: the 1156 and the 1073, both of which are ANSI-standardized bulbs for the US and Canadian markets.
Both the 1156 and 1073 are single-filament bulbs operating at 12 volts, sharing the same BA15s bayonet base configuration.
The BA15s bayonet base is a single-contact design, which is consistent with single-filament applications such as back up lights that require only one circuit.
The 1156 is rated at 21 watts, while the 1073 is rated at 13 watts, making the 1073 a lower-output variant despite the shared base type.
The Buick Special (1961-1969) uses the 1156 bulb for the back up light position.
The 1954-1958 model years use the 1073 bulb instead.
Although the 1156 and 1073 share the same BA15s bayonet base, their wattage ratings differ significantly, and substituting one for the other may result in incorrect light output for the intended circuit.