The Mercedes-Benz 380SEL uses a P21/5W bulb size for front side markers and a 3893 bulb size for rear side markers. The replacement chart covers vehicle production spanning 1981 to 1983.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz 380SEL uses two distinct bulb standards across its front and rear side marker positions for the 1981-1983 model years, reflecting a split between European and North American lighting specifications.
The P21/5W is an ECE-standard dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, mounted on a BAY15d bayonet base. Its dual-filament design allows it to serve both a primary signalling function and a lower-intensity secondary function within a single housing.
The 3893 is an ANSI-standard dual-filament bulb also operating at 12V and sharing the BAY15d bayonet base, though it is classified as a specialty application bulb under North American standards rather than a general-purpose signalling type.
The front side marker positions on the 380SEL for 1981-1983 are specified exclusively for the P21/5W, placing them within ECE regulatory compliance rather than the ANSI framework used at the rear.
The rear side marker positions on the 380SEL for 1981-1983 are specified exclusively for the 3893, which follows ANSI standards applicable to the US and Canadian markets.
Both the P21/5W and the 3893 share the BAY15d bayonet base type. The BAY15d base features two offset pins at different heights, a design that prevents incorrect single-filament bulbs from being seated in dual-filament sockets.
Despite sharing the same base type, the P21/5W and 3893 are not interchangeable without verification, as they originate from different regulatory standards with differing wattage ratings and application classifications.
The consistent use of the same bulb size across all three model years in each position indicates that no specification change occurred within the 1981-1983 production run of the 380SEL for either the front or rear side marker circuits.