Dodge Sierra Map Light Bulb Size

The Dodge Sierra map light requires bulb size 90 or 1004 depending on the specific configuration of the vehicle. Data for the bulb requirements covers the range from 1956 to 1959.

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
1957-1959	90
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 Dodge Sierra map light specifications cover model years 1956-1959, with two distinct bulb types used across this range.
The type 90 bulb is an ANSI-standard single-filament bulb rated at 12V and 13W, fitted with a BA15s bayonet base, and it serves the 1957-1959 model years.
The BA15s base designation indicates a single-contact bayonet fitting, which is not interchangeable with dual-contact bayonet bases without modification.
The 1956 Dodge Sierra uses the type 1004 bulb, a dual-filament unit with a BAY15d bayonet base rated at 12V and 21/5W.
The BAY15d base on the 1004 bulb features offset pins, a design that physically prevents incorrect installation of single-contact alternatives.
The 1004 bulb is noted as a variant of the 1157, meaning the two share a similar dual-filament, dual-wattage configuration, though they are not confirmed as direct substitutes within these specifications.
The wattage difference between the type 90 (13W) and the type 1004 (21/5W dual-filament) reflects a fundamental difference in electrical load, making the two types incompatible with each other's sockets.
Both bulb types conform to ANSI standards applicable in the United States and Canada.