Chevrolet Caprice Headlight Bulb Size

Additional Notes

• The H7 bulb is the high beam type used in the Chevrolet Caprice from 2011-2017. It is a single-filament halogen bulb rated at 12V and 55W, fitted with a PX26d base, and standardized under ECE regulations with approval also granted in the US and Japan.
• The low beam position on the 2011-2017 Caprice uses the H11 bulb, another ECE-standard single-filament halogen type rated at 12V and 55W. Its PGJ19-2 base is distinct from the PX26d base of the H7, meaning the two bulbs are not interchangeable despite sharing the same wattage rating.
• The 9004 bulb, used in both the high and low beam positions on the 1991-1992 Caprice, is a dual-filament halogen type. A single 9004 unit handles both functions, operating at 65W on high beam and 45W on low beam, with a P29t base under ANSI standardization.
• The 1987-1990 Caprice splits its headlight functions between two separate single-filament bulbs: the 9005 (65W, P20d base) for high beam and the 9006 (55W, P22d base) for low beam. Although these bulbs share a similar physical form, their base types and wattage ratings differ, and they are not interchangeable.
• From 1977-1986, the Caprice used 4x6-inch rectangular sealed beam units. The H4651 served the high beam position across all those years, while the low beam position used H4652 in some years and H4656 in others. All three are sealed beam units of the same physical format, but they are distinct part numbers and are not substitutes for one another.
• The 1966-1976 Caprice used sealed beam units in a round format. The H5001 (4-inch square, high beam) and H5006 (5.75-inch round, low beam) are both ANSI-standard sealed beam units rated at 12V. As with all sealed beam types in these specifications, the entire unit is replaced rather than an internal bulb.
• Sealed beam units such as the H4651, H4652, H4656, H5001, and H5006 are self-contained glass assemblies in which the filament, reflector, and lens form a single sealed unit. This construction differs fundamentally from the replaceable-bulb housings used in the 1987-2017 model years.
• The transition from ANSI-standard bulbs (9004, 9005, 9006) in the 1987-1992 Caprice to ECE-standard bulbs (H7, H11) in the 2011-2017 Caprice reflects a change in base type and regulatory standard. ANSI and ECE bulbs use incompatible bases, so fitment is specific to the housing designed for each standard.