Mercedes-Benz SLK320 Back Up Light Bulb Size

The Mercedes-Benz SLK320 back up light utilizes 1156 and P21W bulb sizes according to the provided technical specifications for the lighting system. Data for the specific bulb sizes covers the range from 2001 through 2004.

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
2001-2004	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Mercedes-Benz SLK320 uses the 1156 bulb for the back up light across the 2001-2004 model years.
The 1156 is an ANSI-standardized bulb type, meaning its physical and electrical specifications are governed by a recognized North American standard shared across the US and Canada.
This bulb operates on a 12-volt electrical system and draws 21 watts, which is typical of incandescent automotive reverse lighting applications.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, as opposed to dual-filament types that handle two functions such as braking and running light simultaneously.
The BA15s designation refers to a bayonet-style base with a 15mm collar and a single locating pin, which locks the bulb into its socket with a push-and-twist motion.
The single-pin BA15s base is not interchangeable with the BA15d base, which carries two offset pins and is used on dual-filament bulbs. Substituting one for the other is not physically compatible.