Buick Park Avenue Back Up Light Bulb Size

The Buick Park Avenue back up light utilizes 3057, 1156, and P21W bulb sizes depending on the specific production period. Available information covers the span from 1991 through 2005.

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
1997-2005	3057
1991-1996	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3057
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Buick Park Avenue backup light specifications cover model years 1991 through 2005, during which two distinct bulb types were used across the vehicle's production run.
The 3057 is the backup light bulb for the Buick Park Avenue across model years 1997-2005. It is a dual-filament wedge bulb in a T25 form factor, rated at 12V with filaments drawing 27W and 7W respectively.
The 1156 is the specified backup light bulb for model years 1991-1996. It is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W.
Both the 3057 and 1156 bulbs conform to ANSI standards recognized in the United States and Canada.
The 3057 and 1156 are not interchangeable. The 3057 uses a wedge base while the 1156 uses a BA15s bayonet base, meaning the two bulbs require physically different sockets.
The dual-filament design of the 3057 provides two separate circuits within a single bulb, whereas the 1156 operates on a single circuit. This difference in filament count further distinguishes the two bulbs beyond their base types.
The 3057 draws more wattage on its primary filament (27W) than the 1156 (21W), reflecting a difference in light output between the two bulb types.