The Plymouth PB100 high beam headlight bulb size includes H4651 and H6024 options, while low beam headlight bulb size encompasses H4656, H4652, and H6024 specifications. The replacement chart covers 1975 to 1980 production years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Plymouth PB100 uses two distinct sealed beam form factors across its 1975-1980 model years: a 7-inch round unit and a 4x6-inch rectangular unit. Both operate at 12V and conform to ANSI standards recognized in the United States and Canada.
Sealed beam units such as the H6024, H4651, H4652, and H4656 are not serviceable in the conventional sense. When a sealed beam fails, the entire unit is replaced rather than an internal filament or bulb element.
The Plymouth PB100 (1975-1978) uses the H6024 for both high and low beam positions. This 7-inch round sealed beam unit serves a dual-function role across those model years.
For the 1979-1980 model years, the PB100 transitions to rectangular sealed beam units, with the H4651 assigned to the high beam position in both years.
The low beam position on the PB100 differs between 1979 and 1980. The 1979 model uses the H4652, while the 1980 model uses the H4656. Both are 4x6-inch rectangular sealed beam units, though the H4652 is specifically noted as a variant of the H4651.
Because the H4652 and H4651 are distinct part numbers despite sharing the same form factor, substituting one for the other without confirming beam pattern compatibility would be inadvisable. The H4652 is a variant, not an identical replacement.
The H4656 and H4652 share the same 4x6-inch rectangular sealed beam format but carry different designations, reflecting differences in their optical output characteristics suited to high beam versus low beam applications.