Peugeot 504 Headlight Bulb Size

Additional Notes

• The Peugeot 504 headlight specifications cover the 1969-1983 model years and reference five distinct sealed beam unit types across the high beam and low beam positions: H5001, H4651, H5006, H4656, and H4652.
• All five bulb types are ANSI-standardized sealed beam units rated at 12V. In a sealed beam design, the reflector, lens, and filament are fused into a single glass unit, meaning the entire assembly is replaced rather than an individual bulb.
• The H5001 is a 4-inch square sealed beam unit and serves as the high beam for the 504 across the majority of its production span, covering 1969-1976 and 1980-1983.
• The H5006 is a 5.75-inch round sealed beam unit and functions as the low beam counterpart to the H5001, appearing in the same years: 1969-1976 and 1980-1983.
• For the 1977 and 1979 model years, the Peugeot 504 used the H4651 (high beam) and H4656 (low beam), both of which are 4x6-inch rectangular sealed beam units. The rectangular format differs physically from the square and round units used in other years, making these units non-interchangeable with H5001 or H5006.
• The 1978 low beam position is the only instance in the specifications where the H4652 appears. The H4652 is a variant of the H4651 and shares the same 4x6-inch rectangular sealed beam format, though it is a distinct part designation and is not a direct substitute for the H4651 without verification.
• The H4651 and H4656 share the same physical 4x6-inch rectangular form factor but occupy different beam positions and carry different ANSI designations, which reflects differences in filament placement and light output characteristics. These two types are not interchangeable with each other.
• Because the high beam and low beam positions on the 504 use separate sealed beam units in all listed years, each position requires its own correctly designated replacement unit. Substituting a high beam unit into a low beam position, or vice versa, would not conform to the original specifications.