Buick Super Dome Light Bulb Size

The Buick Super dome light requires bulb size 90 or 1004 depending on the specific application for the interior illumination system. Data for the bulb specifications covers the period from 1954 through 1958.

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
1957-1958	90
1954-1956	1004

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 13W.	90
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W.	1004

Other Locations

Additional Notes

The two bulb types listed across these dome light specifications are the 90 and the 1004, both of which conform to ANSI standards recognized in the US and Canada.
The 90 bulb is a single-filament type rated at 12V and 13W, mounted on a BA15s bayonet base. The BA15s designation indicates a single-contact bayonet fitting with a 15mm base width.
The 1004 bulb is a dual-filament type rated at 12V with a 21/5W output, mounted on a BAY15d bayonet base. The BAY15d base differs from the BA15s in that it has two offset pins, which physically prevents incorrect single-filament bulbs from being seated in a dual-filament socket.
The 1004 is noted as a variant of the 1157, a widely used automotive bulb. Despite this relationship, the two are not always interchangeable, as minor differences in pin offset and wattage ratings can affect fitment and circuit compatibility.
The Buick Super used the 1004 bulb for its dome light across the 1954-1956 model years, then transitioned to the 90 bulb for the 1957-1958 model years.
The shift from a dual-filament 1004 to a single-filament 90 represents a reduction in wiring complexity for the dome light circuit, as a single-filament application requires only one active contact in the socket rather than two.
The 90 and 1004 bulbs use different bayonet base types and are not interchangeable with each other, meaning a replacement bulb must match the exact base type specified for the model year in question.