The Mercedes-Benz SL500 tail light requires a P21/4W bulb size for proper installation and function within the rear lighting assembly. Available data covers the period from 1994 to 2002.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The outer tail light positions on the Mercedes-Benz SL500 use the P21/4W bulb type across the 1994-2002 model years.
The P21/4W is an ECE-standard bulb, meaning it conforms to European and international automotive lighting regulations rather than SAE standards used in North American markets.
P21/4W is a dual-filament bulb, operating at two distinct wattages within a single unit: 21 watts for the higher-intensity function and 4 watts for the lower-intensity function.
The bulb operates on a 12-volt electrical system, which is consistent with standard passenger vehicle architecture.
The P21/4W uses a BAZ15d bayonet base, which is an offset twin-contact fitting. The asymmetric pin placement of the BAZ15d base is a deliberate design feature that prevents incorrect filament orientation during installation.
The BAZ15d base is specific to dual-filament bulbs and is not interchangeable with the BA15s single-contact or BA15d symmetrical twin-contact bayonet bases, despite their similar physical scale.