The Mercedes-Benz 560SEL uses a P21/5W bulb size for the front turn signal and a P21W bulb size for the rear turn signal. The replacement chart covers vehicle production spanning 1986 to 1991.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercedes-Benz 560SEL uses two distinct bulb types across its turn signal positions: the P21/5W for the front and the P21W for the rear, both governed by ECE standards used in Europe and worldwide markets.
Both bulb types operate on a 12-volt electrical system, which is standard for automotive lighting applications of this era.
The P21/5W is a dual-filament bulb, meaning it contains two separate filaments within a single housing, rated at 21 watts and 5 watts respectively.
The P21W is a single-filament bulb rated at 21 watts, dedicated solely to the turn signal function at the rear of the vehicle.
The P21/5W uses a BAY15d bayonet base, which features two offset pins at different heights to ensure correct orientation during installation.
The P21W uses a BA15s bayonet base, a single-contact design with two pins at the same height, making it physically incompatible with the BAY15d socket used by the P21/5W.
Because the BAY15d and BA15s bases are not interchangeable, the front and rear turn signal bulbs of the 560SEL cannot be substituted for one another despite sharing the same 21-watt primary output.
The front turn signal position of the 560SEL specifies the P21/5W across all model years from 1986-1991, and the rear turn signal position specifies the P21W across the same span.