Mercedes-Benz 350SDL front side marker bulb uses P21/5W size while rear side marker bulb uses 3893 size. The replacement chart covers 1990 to 1991 vehicle 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 350SDL uses two distinct bulb types across its front and rear side marker positions for the 1990-1991 model years.
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.
The BAY15d bayonet base features offset pins, which physically prevent incorrect single-filament bulbs from seating in sockets designed for dual-filament applications.
The 3893 is an ANSI-standard dual-filament bulb also using a BAY15d bayonet base, rated at 12V and designated for specialty automotive applications in the US and Canadian markets.
The front side marker positions on the 350SDL for 1990-1991 call for the P21/5W, which follows European and worldwide ECE certification standards.
The rear side marker positions on the 350SDL for 1990-1991 call for the 3893, which follows North American ANSI standards rather than ECE standards.
Although both the P21/5W and the 3893 share the BAY15d bayonet base, they are governed by different regulatory standards and are not confirmed as interchangeable across the front and rear positions on this vehicle.