Buick Century Headlight Bulb Size

Additional Notes

• The Buick Century used the 9005 bulb for high beam and the 9006 for low beam across the 1997-2005 model years. Both are single-filament halogen bulbs operating at 12V with a P20d and P22d base, respectively, and are individually replaceable rather than sealed units. The 9005 draws 65W while the 9006 draws 55W.
• The 9005 and 9006 share the same general halogen bulb family but are not interchangeable. Their base types differ, with the P20d on the 9005 and the P22d on the 9006, meaning each position requires its specific bulb type.
• From 1973-1975 and 1954-1957, the Buick Century used the H6024, a 7-inch round sealed beam unit rated at 12V, for both high and low beam positions. As a sealed beam, the entire unit is replaced rather than an internal bulb.
• The H6054, a 5x7-inch rectangular sealed beam unit, served both the high and low beam positions on the Century for the 1978-1981 model years. Like all sealed beam units in these specifications, it operates at 12V and is replaced as a whole assembly.
• For the 1982-1985 model years, the Century used separate sealed beam units for each beam position: the H4651 for high beam and the H4652 for low beam. Both are 4x6-inch rectangular sealed beam units, with the H4652 noted as a variant of the H4651.
• The 1976-1977 model years show a split between beam positions. The high beam used the H4651, a 4x6-inch rectangular sealed beam, while the low beam used the H4656, a separate 4x6-inch rectangular sealed beam unit.
• The 1958 Century used distinct sealed beam units for each position: the H5001, a 4-inch square sealed beam, for high beam, and the H5006, a 5.75-inch round sealed beam, for low beam. This makes 1958 the only year in the specifications where the two beam positions used sealed beams of different physical shapes.
• All sealed beam types listed across these specifications, including the H4651, H4652, H4656, H5001, H5006, H6024, and H6054, conform to ANSI standards applicable in the US and Canada, and all operate at 12V.