The Mercedes-Benz 560SL uses a P21/5W bulb size for front turn signals and a P21W bulb size for rear turn signals. The replacement chart covers 1986 through 1989 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 560SL uses two distinct bulb types across its turn signal positions for the 1986-1989 model years: P21/5W at the front and P21W at the rear.
The P21/5W is a dual-filament bulb rated at 12V with a 21W primary filament and a 5W secondary filament, housed in a BAY15d bayonet base.
The BAY15d base features two offset pins at different heights, a design that physically prevents incorrect filament orientation during installation.
The P21W is a single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base, which uses a single locating pin rather than the dual-pin arrangement of the BAY15d.
Because the P21/5W and P21W share the same 21W main filament wattage but differ in base type and filament count, the two bulbs are not interchangeable with each other.
Both bulb types conform to ECE standards, a regulatory framework recognized across Europe and numerous other markets worldwide.
The front turn signal position requires the P21/5W across all four listed model years, indicating the front housing is designed to accommodate a dual-filament bulb.
The rear turn signal position calls for the P21W across the same 1986-1989 span, meaning the rear circuit is wired for a single-filament application only.