Chevrolet Impala Headlight Bulb Size

Additional Notes

• The D3S is a mercury-free HID (xenon) discharge bulb operating at 42V and 35W, with a PK32d-5 base and an integral ignitor designed specifically for projector-type housings. In the Chevrolet Impala, it appears across the 2014-2020 model years as the headlight bulb for both high and low beam positions on vehicles equipped with HID headlamps.
• The 9012 is a single-filament enhanced halogen bulb rated at 12V and 55W with a PX22d base. It serves as both the high and low beam bulb on the Impala for 2014, 2015, and 2020 with halogen capsule headlamps, meaning a single bulb type handles both functions in those years rather than separate high and low beam bulbs.
• For the 2016-2019 Impala with halogen capsule headlamps, the high beam position uses a 9005 (65W), while the low beam position uses either a 9005 (2016-2019) or H11 (2006-2013), depending on the year. The 9005 and 9006 share a similar physical form but differ in wattage and base type, making them non-interchangeable despite their visual resemblance.
• The 9004 is a dual-filament halogen bulb rated at 65W for high beam and 45W for low beam, operating from a single P29t base. The Chevrolet Impala used this bulb for both high and low beam positions across the 1994-1996 model years, consolidating both functions into one socket per headlight assembly.
• The H9 and H11 are both ECE-standard halogen bulbs approved for use in the United States, but they are not interchangeable. The H9 uses a PGJ19-5 base and operates at 65W, while the H11 uses a PGJ19-2 base at 55W. The Impala used H9 for high beam and H11 for low beam across the 2006-2013 model years.
• From 1977-1985, the Chevrolet Impala used 4x6-inch rectangular sealed beam units. The high beam position used the H4651 across all those years, while the low beam position varied between the H4652 and H4656 depending on the specific year. All three are sealed beam units where the entire housing is replaced rather than an individual bulb.
• The H5001 and H5006 are sealed beam units used in the Impala from 1958-1976. The H5001 is a 4-inch square unit used for high beam, and the H5006 is a 5.75-inch round unit used for low beam. Both are ANSI-standard sealed beam designs operating at 12V, where the lens, reflector, and filament form a single non-separable assembly.
• The 9005 and 9012 bulbs share the same P20d and PX22d base types respectively and are both single-filament ANSI halogen bulbs, but the 9012 is an enhanced variant producing more light output at a lower wattage (55W versus 65W for the 9005). The two are not directly interchangeable, which accounts for the distinct fitment split seen between the 2015 and 2016-2019 Impala halogen configurations.