Pontiac Parisienne high beam headlight bulbs measure H4651 in size, while low beam headlight bulbs measure H4656 or H4652 in size. The replacement chart covers 1983 to 1986 vehicle production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H4651 and H4656 are both ANSI-standardized 4x6-inch rectangular sealed beam units operating at 12V, meaning the entire lens-and-filament assembly is replaced as one unit rather than housing a separate replaceable bulb inside.
The H4651 serves as the high beam unit across all four model years covered (1983-1986) in the Pontiac Parisienne specifications, making it the most consistently applied bulb type in this dataset.
The H4656 is designated for low beam use in 1983 and 1985-1986, while 1984 uses the H4652 instead, indicating that the low beam position does not carry a single uniform fitment across all listed years.
The H4652 is described as a variant of the H4651, sharing the same ANSI-standard 4x6-inch rectangular sealed beam format and 12V rating, though it is a distinct part number and is not interchangeable without verification.
Because all three bulb types (H4651, H4656, H4652) share the same physical format and voltage rating, their differences relate to beam function and filament configuration rather than housing size or electrical system compatibility.
The sealed beam construction of all listed units means that physical damage to the lens or any internal failure requires full unit replacement, as no internal component is serviceable separately.
ANSI standardization across all three bulb types indicates that fitment follows a regulated specification recognized in both the United States and Canada, rather than a proprietary or manufacturer-specific design.
The 1984 low beam fitment with the H4652 diverges from the H4656 used in the surrounding years, which represents a year-specific variation that warrants attention when sourcing a replacement for that model year.