Plymouth Duster Dome Light Bulb Size

The Plymouth Duster dome light requires 1004 or 257 bulb sizes depending on the specific vehicle configuration. Available information covers a production span from 1970 through 1976.

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
1972-1976	1004
1971	257
1970	1004

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. Variant of 1157. 12V, 21/5W.	1004
ANSI standard (US & Canada). Festoon or BA9s base instrument bulb. 12V, 2W.	257

Other Locations

Additional Notes

The 1004 is an ANSI-standardized bulb used in both the United States and Canada. It operates at 12 volts with a dual-filament output rated at 21/5 watts, and it seats into a BAY15d bayonet base.
The 1004 is a variant of the more widely known 1157 bulb. The two share the same BAY15d base and dual-filament design, though they are not identical and the distinction is relevant when sourcing replacements.
The Plymouth Duster uses the 1004 bulb for its dome light across the 1972-1976 model years, as well as the 1970 model year.
The 1971 Plymouth Duster is the sole model year in these specifications to use the 257 bulb for the dome light rather than the 1004.
The 257 is also an ANSI-standardized bulb for the US and Canadian market. It operates at 12 volts and draws only 2 watts, making it a considerably lower-output lamp than the 1004.
The 257 is available in either a festoon-style or BA9s base configuration. Because the 1004 uses a BAY15d bayonet base, the two bulbs are not interchangeable despite both appearing in the same dome light application across adjacent model years.