Mercedes-Benz C220 front side marker bulbs measure P21/5W in size, while rear side marker bulbs measure 12821, with each bulb type serving distinct lighting functions on the vehicle. The replacement chart covers 1994 to 1996 model production years and documents bulb size specifications for both front and rear side marker positions.
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 front and rear side marker positions for the 1994-1996 model years.
The P21/5W is a dual-filament bulb operating at 12V with a 21W main filament and a 5W secondary filament, mounted on a BAY15d bayonet base.
The BAY15d base features offset pins, which physically prevents incorrect single-filament bulbs from seating in the socket, as the pin positions are not symmetrical.
The P21/5W follows ECE regulatory standards, a certification framework used across Europe and numerous other markets worldwide.
The front side marker position on the C220 (1994-1996) uses the P21/5W, meaning the socket is designed specifically for a dual-filament BAY15d fitment.
The 12821 is a Philips part number designation for a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W.
The W2.1x9.5d base is a wedge-type fitting, meaning the bulb is held in place by the tension of the socket contacts rather than a locking bayonet mechanism.
The rear side marker position on the C220 (1994-1996) uses the 12821, a single-filament wedge bulb, which is not interchangeable with the dual-filament BAY15d P21/5W used at the front.
The front and rear side marker sockets on the C220 are physically incompatible with each other, as the BAY15d bayonet base and the W2.1x9.5d wedge base are entirely different fitment types.
Substituting a single-filament bulb for the P21/5W at the front position would not be a direct replacement, as the BAY15d socket is engineered around the dual-filament configuration.