The Buick Rainier high beam headlight uses a 9005 bulb size while the low beam headlight requires a 9006 bulb size. Replacement specifications in the chart cover 2004 through 2007 model years.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Buick Rainier uses the 9005 bulb for high beam headlights and the 9006 bulb for low beam headlights across all model years from 2004-2007.
The 9005 is a single-filament halogen bulb rated at 12V and 65W, operating on a P20d base and conforming to ANSI standards recognized in both the United States and Canada.
The 9006 is also a single-filament halogen bulb rated at 12V but draws 55W rather than 65W, and it uses a P22d base rather than the P20d base found on the 9005.
The difference in base types between the 9005 (P20d) and the 9006 (P22d) means the two bulbs are not physically interchangeable, despite their otherwise similar construction and voltage rating.
The 10-watt difference between the high beam 9005 and the low beam 9006 reflects a standard design practice in which high beam circuits are allocated greater wattage to produce a longer-range, higher-intensity output.
Single-filament construction in both bulb types means each serves a dedicated function, with no shared filament between high and low beam operation as would be found in a dual-filament bulb such as the 9007 or H4.