The Mercedes-Benz E300 tail light utilizes 5008, 12821, and P21/4W bulb sizes according to the provided data. The information covers the range from 1995 to 1999 for the specified vehicle.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz E300 outer tail light draws from two distinct bulb categories across its 1995-1999 model years: miniature wedge-type bulbs and bayonet-base signalling bulbs.
The 12961 and 12821 are both Philips part numbers designating T10 miniature wedge bulbs sharing the same W2.1x9.5d base, 12V operating voltage, and 5W output, making them functionally interchangeable in positions where either is specified.
The P21/4W is an ECE-standard dual-filament bulb rated at 12V with a 21W primary filament and a 4W secondary filament, mounted on a BAZ15d offset bayonet base. The offset pin spacing of the BAZ15d base is a deliberate anti-misinstallation feature, preventing the bulb from being seated in the wrong orientation.
The P21W is an ECE-standard single-filament bulb rated at 12V and 21W, using a BA15s bayonet base with symmetrical pin spacing. Because the BA15s and BAZ15d bases differ in pin offset, P21W and P21/4W bulbs are not interchangeable despite their similar appearance.
The 5008 is an ANSI-standard single-filament bulb on a BA15s bayonet base, operating at 12V. It is described as a lower-wattage variant of the 1156 bulb type, meaning it shares the same base but draws less power.
For the 1997-1999 E300, one outer tail light position consistently uses the 12961 bulb, while the second position varies by year, with the 1999 model using P21/4W, the 1998 model using 12821, and the 1997 model using P21/4W.
The 1996 E300 outer tail light uses P21/4W in one position and 12821 in the other, combining an ECE bayonet-base signalling bulb with a T10 wedge bulb within the same assembly.
The 1995 E300 outer tail light uses P21W in one position and 5008 in the other. Both share the BA15s bayonet base, but they originate from different standards bodies, with P21W following ECE classification and 5008 following ANSI classification.
The ECE-standard bulbs (P21W and P21/4W) and the ANSI-standard 5008 are not defined by a single manufacturer's part number, meaning multiple brands produce conforming versions under those designations.
The T10 wedge base (W2.1x9.5d) used by both the 12961 and 12821 is a tool-free push-in fitting, mechanically distinct from the twist-lock bayonet bases used by the P21W, P21/4W, and 5008 bulbs in the same specifications.