Studebaker Avanti Dome Light Bulb Size

The Studebaker Avanti dome light requires a 1004 bulb size for proper interior illumination. The replacement chart covers 1963 to 1964 production years with corresponding bulb specifications.

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
1963-1964	1004

Bulb Specifications

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

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Additional Notes

The 1004 bulb is the sole dome light bulb size listed for the Studebaker Avanti, covering the 1963-1964 model years.
The 1004 is an ANSI-standardized bulb type recognized in both the United States and Canada.
It is a dual-filament bulb, meaning it contains two separate filaments within a single envelope, each operating at a different wattage.
The 1004 operates on a 12-volt electrical system at 21/5 watts, with the higher wattage filament and lower wattage filament serving distinct lighting functions.
The 1004 uses a BAY15d bayonet base, a two-pin base type where the two pins are offset at different heights to ensure correct orientation during installation.
The 1004 is a variant of the 1157 bulb. These two types share the same BAY15d base and dual-filament design, though they differ in their electrical ratings, which means they are not directly interchangeable without accounting for those differences.