The Mercedes-Benz SLK32 AMG tail light requires bulb size 67 or 12821 depending on the specific application. Data for the tail light covers the range from 2002 to 2004.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz SLK32 AMG outer tail light draws from two distinct bulb standards across its model years: the ANSI standard used in the United States and Canada, and the ECE standard used in Europe and worldwide markets.
The 1156 is an ANSI-standard, single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base. It is specified for the outer tail light on the 2003-2004 SLK32 AMG in North American market configurations.
The PY21W is the ECE-standard counterpart to the 1156 for the 2002 model year. It is also a single-filament, 12V, 21W bulb, but it produces an amber output and uses a BAU15s bayonet base rather than the BA15s base of the 1156.
The BA15s and BAU15s bayonet bases are physically similar but not interchangeable. The BAU15s base has an offset pin alignment, which prevents a PY21W from seating correctly in a socket designed for a BA15s 1156, and vice versa.
The 2004 model year outer tail light also references bulb 67, an ANSI-standard single-filament bulb with a BA15s bayonet base rated at 12V and 8W. Although it shares the same base type as the 1156, its significantly lower wattage output distinguishes it as a separate fitment position rather than a substitute.
The 12821 is a Philips part number designating a miniature wedge-style T10 bulb with a W2.1x9.5d base, rated at 12V and 5W. It is specified for the outer tail light on the 2002-2003 model years, occupying a different socket position from the 1156 or PY21W on those same vehicles.
The W2.1x9.5d wedge base of the 12821 is physically incompatible with the bayonet sockets used by the 1156, PY21W, and 67 bulbs, as the two base types rely on entirely different retention and contact mechanisms.