The Citroen D Special uses an H5001 bulb size for high beam headlight operation and an H5006 bulb size for low beam headlight operation. The replacement chart covers vehicle production years spanning 1970 to 1972 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 H5001 and H5006 are sealed beam units built to ANSI standards for the US and Canadian markets. In both types, the lens, reflector, and filament are fused into a single glass envelope, meaning the entire unit is replaced rather than an individual bulb.
The Citroen D Special uses the H5001 for high beam across the 1970-1972 model years. This unit follows the 4-inch square sealed beam format operating at 12 volts.
The H5006 fills the low beam position across the same 1970-1972 span. It is a 5.75-inch round sealed beam unit, also rated at 12 volts.
The physical format differs between the two positions. The square profile of the H5001 and the round profile of the H5006 are not interchangeable, as housing geometry in the vehicle is specific to each shape.
Both units share the same 12-volt operating requirement, which aligns with the standard 12-volt electrical systems found in passenger vehicles of this era.
Because sealed beam units are self-contained, the optical output is fixed at the factory. No adjustment to the internal components is possible after manufacture.