The Peugeot 505 brake light uses a P21W bulb size for the rear lighting system. Available data covers the period from 1980 through 1991 for the specified vehicle components.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Peugeot 505 uses the P21W bulb across all listed model years for its brake light application, spanning 1980-1991.
The P21W is an ECE-standardized bulb, meaning it conforms to European and internationally recognized automotive lighting regulations rather than SAE standards used in North American markets.
The P21W operates at 12 volts with a 21-watt output, which is a wattage typical of single-filament stop and signal applications where a distinct, high-visibility light is required.
The bulb uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and the lowercase "s" indicates a single contact at the base, confirming its single-filament design.
Because the P21W carries only one filament, it serves a dedicated function rather than a combined stop-and-tail role, which would require a dual-filament bulb such as the P21/5W.
The Peugeot 505 Center High Mount Stop Light also uses the P21W for model years 1986-1991, making the brake circuit consistent across both the standard brake lights and the third braking light position during that period.
The BA15s base is not interchangeable with the BA15d base, which carries two offset contact pins. Substituting a BA15d bulb into a BA15s socket is not a compatible fitment.
The P21W shares its BA15s base with several other bulb types of differing wattages, so base compatibility alone does not confirm electrical or photometric suitability as a replacement.