The Mercedes-Benz 500SL uses a P21/5W bulb size for the front side marker and a 5008 bulb size for the rear side marker. The replacement chart covers 1990 to 1993 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 500SL uses two distinct bulb types across its front and rear side marker positions for the 1990-1993 model years, with each position requiring a different bulb standard.
The P21/5W is an ECE-standard bulb, meaning it conforms to European and international regulations rather than North American ANSI standards. It operates on a 12V circuit and carries a dual-filament design rated at 21W and 5W respectively.
The dual-filament nature of the P21/5W means the bulb serves two separate electrical functions within a single housing, with the higher 21W filament and the lower 5W filament activated independently depending on the signaling requirement.
The P21/5W uses a BAY15d bayonet base. The BAY15d designation indicates an offset pin configuration, which physically prevents the bulb from being seated incorrectly and ensures the two filaments align with their corresponding contacts.
The front side marker position on the 500SL (1990-1993) is fitted with the P21/5W across all four model years.
The rear side marker position across the same 1990-1993 model years uses the 5008, an ANSI-standard bulb intended for the US and Canadian markets.
The 5008 is a single-filament bulb, contrasting directly with the dual-filament P21/5W used at the front. It operates on a 12V circuit and is classified as a lower wattage variant of the 1156 bulb family.
The 5008 uses a BA15s bayonet base. Unlike the BAY15d base of the P21/5W, the BA15s features a single-contact, symmetrical pin arrangement, making the two bases physically incompatible with each other despite both being bayonet-style fittings.
Because the front and rear side marker bulbs on the Mercedes-Benz 500SL use different base types, the P21/5W and 5008 are not interchangeable between positions.