Mercedes-Benz SL600 Back Up Light Bulb Size

The Mercedes-Benz SL600 back up light requires a P21W bulb size for proper installation and function within the rear lighting assembly. Available data covers the specific range from 1994 through 2009 for the specified vehicle components.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2004-2009	P21W
1994-2002	P21W

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W

Other Locations

Additional Notes

The Mercedes-Benz SL600 uses the P21W bulb across all listed model years, spanning 1994-2009, with the sole exception of 2003, which is not present in the specifications.
The P21W is an ECE-standardized bulb type, meaning its specifications are governed by the Economic Commission for Europe regulatory framework, which is widely adopted across European and international automotive markets.
P21W bulbs operate at 12 volts with a 21-watt output, which is a standard rating for single-filament signalling applications such as backup lights.
The P21W uses a BA15s bayonet base, where "BA" denotes a bayonet cap fitting, "15" refers to the 15mm base width, and the lowercase "s" indicates a single-contact configuration.
Because the P21W is a single-filament bulb, it serves one dedicated function per housing, as opposed to dual-filament types that combine two functions, such as braking and running light, within a single bulb.
The BA15s bayonet mount is a twist-and-lock style fitting, which physically distinguishes it from wedge-base and screw-base bulb types that are not interchangeable with it.
The consistent use of the P21W across the entire 1994-2009 model year range of the SL600 reflects a stable backup light circuit specification throughout multiple generations of the vehicle.