The Mercedes-Benz E300 front side marker uses bulb sizes 12961, 12821, or P21/5W, while the rear side marker requires 12821 or 232 bulb sizes. The replacement chart covers 1995 to 1999 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz E300 front side marker position uses two different T10 wedge bulbs across its model years: the Philips 12961 for 1997-1999 and the Philips 12821 for 1996. Both share the same W2.1x9.5d base, 12V rating, and 5W output, making them electrically and physically equivalent despite carrying different Philips part numbers.
The rear side marker position on the E300 uses the Philips 12821 across 1996-1999, a T10 miniature wedge bulb rated at 12V and 5W with a W2.1x9.5d base.
The 1995 E300 front side marker takes a P21/5W bulb, which follows the ECE standard used in Europe and worldwide markets. This is a dual-filament bulb with a BAY15d bayonet base rated at 12V with filaments drawing 21W and 5W respectively.
The BAY15d base of the P21/5W is a double-contact bayonet fitting with offset pins, a design that prevents incorrect single-filament bulbs from being inserted in its place. This base type is physically incompatible with the W2.1x9.5d wedge base used in the 12961 and 12821.
The 1995 E300 rear side marker takes a 232 festoon bulb, which follows the ANSI standard used in the US and Canada. It uses an SV8.5 base and is rated at 12V and 3W.
A festoon bulb such as the 232 is a cylindrical lamp with metal end caps that seat into spring-loaded holders, a mounting method that is mechanically distinct from both wedge and bayonet base types used elsewhere in these specifications.
The front and rear side marker positions on the 1995 E300 use entirely different bulb types, with the front requiring a dual-filament bayonet bulb and the rear requiring a festoon bulb. These two positions are not interchangeable.
For model years 1996-1999, the rear side marker consistently uses the Philips 12821, while the front side marker transitions from the 12821 in 1996 to the 12961 in 1997. Since both are T10 wedge bulbs with identical base and electrical ratings, the 12961 and 12821 are cross-compatible in those positions.