The Dodge Royal Monaco headlight bulb specifications include H4651 and H5001 sizes for high beam applications, along with H4652 and H5006 sizes for low beam functions, representing the bulb options available for this model. The replacement chart covers 1975 through 1977 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 Dodge Royal Monaco uses sealed beam headlight units across all listed years, meaning the entire lens-and-filament assembly is replaced as a single unit rather than swapping an internal bulb.
All four bulb types present in these specifications, H4651, H4652, H5001, and H5006, conform to ANSI standards recognized in both the United States and Canada, and all operate at 12 volts.
The 1977 Royal Monaco uses a 4x6-inch rectangular sealed beam format, with the H4651 assigned to the high beam position and the H4652 assigned to the low beam position.
The H4651 and H4652 share the same 4x6-inch rectangular form factor, with H4652 designated as a variant of H4651. Despite their physical similarity, the two units are not interchangeable between positions, as each is rated for a specific beam function.
The 1975-1976 Royal Monaco uses a 4-inch square sealed beam unit, the H5001, for the high beam, and a 5.75-inch round sealed beam unit, the H5006, for the low beam, meaning the two headlight positions on those model years use physically distinct unit shapes.
The H5006 round sealed beam format was a widely used ANSI-standard unit across many North American vehicles of that era, which generally means replacement units remain available through multiple suppliers.
The headlight configuration changed between the 1976 and 1977 model years, with the square and round sealed beam units giving way entirely to the rectangular 4x6-inch format, indicating a redesign of the front lighting assembly.
Because sealed beam units are self-contained, fitment is governed strictly by the physical housing shape and ANSI type designation rather than by any separate socket or base compatibility.