Buick GS 400 Back Up Light Bulb Size

The Buick GS 400 back up light requires a P21W bulb size for proper installation and function. Data for the specified lighting component covers the period from 1968 to 1969.

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

YearsUS TypeEU TypeShop
1968-19691156P21WCheck Price

Bulb Specifications

Description Type Shop
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.P21WCheck Price
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.1156Check Price

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