Chevrolet Brookwood Trunk Bulb Size

The Chevrolet Brookwood trunk light requires 89 and 1003 bulb sizes for the specific lighting components located within the rear storage area. Data for the lighting specifications covers the period from 1958 through 1972.

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	89
1969-1971	1003
1958-1961	1003

Bulb Specifications

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

Other Locations

Additional Notes

The 1003 bulb is the most frequently specified trunk bulb across the Chevrolet Brookwood, appearing in model years 1958-1961 and 1969-1971.
The 1003 is an ANSI-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base.
The 89 bulb is specified for the 1972 Chevrolet Brookwood and shares the same ANSI-standard BA15s bayonet base as the 1003.
Although both bulbs use the BA15s bayonet base, the 89 operates at 13W compared to the 1003's 21W, making them non-interchangeable without accounting for the wattage difference.
The 89 is described as a lower-wattage variant of the 1156 bulb, which is itself a common single-filament BA15s type widely used in automotive lighting applications.
Both the 89 and 1003 are recognized under ANSI standards applicable in the United States and Canada.