Mercedes-Benz 380SE front side marker bulbs use a P21/5W size while rear side marker bulbs use a 3893 size. The replacement chart covers 1984 to 1985 model 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 380SE uses two distinct bulb types across its front and rear side marker positions for the 1984-1985 model years, with each position requiring a specific bulb rather than a shared fitment.
The front side marker on the 1984-1985 380SE takes the P21/5W bulb, an ECE-standard type recognized across European and worldwide markets.
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 that prevent incorrect insertion, a design characteristic that distinguishes it from single-filament bayonet bases and ensures polarity-correct installation.
The rear side marker on the 1984-1985 380SE takes the 3893 bulb, an ANSI-standard type used in the United States and Canada.
The 3893 is also a dual-filament bulb with a BAY15d bayonet base, operating at 12V, and is classified as a specialty application bulb under the ANSI standard.
Although both the P21/5W and the 3893 share the BAY15d bayonet base, they are governed by different standards and are not listed as interchangeable within these specifications, as each is assigned to a separate lighting position.
The use of an ECE-standard bulb at the front and an ANSI-standard bulb at the rear reflects a mixed regulatory fitment across the two marker positions on this vehicle.