The Mercedes-Benz 560SL brake light requires a P21W bulb size for proper installation and function within the lighting assembly. Data for the specified component covers the range from 1986 through 1989.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W is the sole bulb type listed across all brake light positions for the Mercedes-Benz 560SL, covering both the standard brake lights and the center high mount stop light.
The P21W operates at 12 volts with a 21-watt output, classifying it as a single-filament bulb intended for signalling functions such as braking indicators rather than continuous illumination.
This bulb follows the ECE (Economic Commission for Europe) standard, a regulatory framework adopted across Europe and numerous other markets worldwide, distinguishing it from SAE-standard bulbs used in North American applications.
The P21W 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, which corresponds directly to its single-filament construction.
The BA15s base is not interchangeable with the BA15d base, which carries a double contact for dual-filament bulbs. Substituting a BA15d bulb in a BA15s socket is not mechanically compatible.
The standard brake lights on the Mercedes-Benz 560SL use the P21W across the 1986-1989 model years.
The center high mount stop light position uses the P21W for the 1986-1987 model years.
Because the P21W is an ECE-standard component, direct substitution with SAE-equivalent bulbs requires verification of base type, wattage, and voltage compatibility before fitment.