Ford Galaxie Map Light Bulb Size

The Ford Galaxie map light utilizes bulb sizes 631 and 1003 and 89 for illumination. Data for the specified components covers the period from 1959 through 1967.

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
1967	631
1962-1966	1003
1959-1960	89

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Variant of 1156. 12V, 21W.	631
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1003
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. Lower wattage variant of 1156. 12V, 13W.	89

Other Locations

Additional Notes

The Ford Galaxie map light specifications span model years 1959 through 1967, covering three distinct bulb types across that range.
The 1003 bulb is the most frequently specified type, appearing in the Ford Galaxie across the 1962-1966 model years.
The 1003 is an ANSI-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base.
The BA15s bayonet base is a single-contact base, meaning it is not interchangeable with dual-contact BA15d variants despite sharing a similar physical form.
The 1967 Ford Galaxie uses the 631 bulb, which is also a 12V, 21W single-filament type with a BA15s base and is classified as a variant of the 1156.
Although the 631 and 1003 share the same voltage, wattage, and base type, they carry distinct ANSI designations, and fitment should follow the year-specific specification rather than treating them as freely interchangeable.
The 1959-1960 model years specify the 89 bulb, which operates at 12V but draws only 13W, making it a lower-wattage type compared to the 631 and 1003.
The 89 is also described as a lower-wattage variant of the 1156 and shares the BA15s bayonet base, though its reduced wattage distinguishes it electrically from the other two types in these specifications.
All three bulb types across these specifications conform to ANSI standards recognized in both the United States and Canada.