Buick Roadmaster License Plate Bulb Size

The Buick Roadmaster license plate light uses bulb sizes 24, 63, and 67 depending on the specific application. Data for the bulb sizes covers the range from 1950 to 1991.

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
1991	24
1954-1958	67
1950-1953	63

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA9s base. 12V, 2W.	24
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 8W.	67
ANSI standard (US & Canada). Single-filament bulb with BA9s base. 12V, 0.63W.	63

Other Locations

Additional Notes

The Buick Roadmaster license plate bulb specifications span model years 1950 through 1958, plus 1991, covering three distinct ANSI-standard bulb types across that range.
The bulb 67 is the most frequently specified type in these records, appearing across the 1954-1958 Roadmaster model years for the license plate position.
The 67 bulb operates at 12V and 8W, uses a BA15s bayonet base, and is a single-filament design. It is technically a lower-wattage variant of the 1156 bulb, which shares the same BA15s base but draws significantly more power.
The BA15s base designation on the 67 bulb indicates a single-contact bayonet fitting with a 15mm base width, a common automotive base type that is not interchangeable with dual-contact BA15d variants.
The 63 bulb is specified for the 1950-1953 Roadmaster, operating at 12V and just 0.63W. It uses a BA9s base, making it physically incompatible with the 67 bulb despite both being single-filament designs.
The BA9s base found on both the 63 and 24 bulbs is a miniature bayonet fitting with a 9mm base width. Although the 63 and 24 share this base type, their wattage differs substantially, at 0.63W and 2W respectively.
The 1991 Buick Roadmaster uses the 24 bulb for its license plate light, rated at 12V and 2W with a BA9s base, placing it in a different bulb family from the 1954-1958 models despite the shared base style with the 63.
The shared BA9s base between the 24 and 63 bulbs does not make them directly interchangeable, as the wattage difference reflects a meaningful gap in light output that may affect compliance with lighting standards.