Mercedes-Benz C220 inner tail light uses a P21/4W bulb size while the outer tail light requires a 12821 bulb size. The replacement chart covers vehicle production years spanning 1994 to 1996 with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz C220 uses two distinct bulb types across its inner and outer tail light positions for the 1994-1996 model years.
The P21/4W is a dual-filament bulb operating at 12V with a 21W/4W output split, where the higher wattage filament serves one signalling function and the lower wattage filament serves another within the same housing.
The P21/4W follows the ECE standard, a regulatory framework used in Europe and internationally, and it uses a BAZ15d bayonet base, which is an offset pin configuration designed to prevent incorrect installation.
The inner tail light position on the C220 uses the P21/4W across all three listed model years, 1994-1996.
The BAZ15d base of the P21/4W is not interchangeable with standard single-filament bayonet bases such as BA15s or BA15d, as the pin offset is specific to dual-filament applications.
The outer tail light position on the C220 uses the 12821 across the 1994-1996 model years.
The 12821 is a Philips part number designating a T10 miniature wedge bulb rated at 12V and 5W, with a W2.1x9.5d wedge base that requires no separate locking mechanism.
The W2.1x9.5d wedge base of the 12821 is a single-filament format and is not compatible with the BAZ15d bayonet socket used by the inner tail light position.
The 5W output of the 12821 is notably lower than either filament rating of the P21/4W, reflecting its role in a lower-intensity tail light position compared to the inner unit.
Because the inner and outer tail light positions on the C220 use mechanically different base types, the two bulb types are not interchangeable between positions.