Pontiac Catalina Map Light Bulb Size

The Pontiac Catalina map light requires bulb size 1004 or 906 depending on the specific application for the interior illumination system. Data for the bulb sizes covers the range from 1962 through 1980.

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
1980	1004
1979	906
1962-1970	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). Miniature wedge bulb (T10). 12V, 8W.	906

Other Locations

Additional Notes

The 1004 bulb is the most frequently specified map light bulb for the Pontiac Catalina, appearing across the 1962-1968 model years and again in 1970 and 1980.
The 1004 is a dual-filament bulb rated at 12V and 21/5W, built on a BAY15d bayonet base. It follows the ANSI standard applicable in both the US and Canada.
As a variant of the 1157, the 1004 shares the same BAY15d bayonet base type, though the two bulbs are not necessarily interchangeable due to differences in wattage and filament ratings.
The 1979 Pontiac Catalina departs from the otherwise consistent 1004 fitment, specifying instead the 906 bulb for the map light position.
The 906 is a single-filament miniature wedge bulb of the T10 type, rated at 12V and 8W. Its wedge base design is physically incompatible with the BAY15d bayonet socket used by the 1004.
The base type difference between the 1004 (BAY15d bayonet) and the 906 (T10 wedge) means the two bulbs cannot be substituted for one another without a socket adapter or housing modification.
At 8W, the 906 draws notably less power than either filament rating of the 1004, which operates at 21W on its primary filament and 5W on its secondary filament.