Mercedes-Benz CLS550 Back Up Light Bulb Size

The Mercedes-Benz CLS550 back up light utilizes a 921 bulb size for the rear lighting system. Available data for the specified vehicle covers the range from 2007 through 2018.

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
2007-2018	921

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921

Other Locations

Additional Notes

The Mercedes-Benz CLS550 uses the 921 bulb size for the back up light across the 2007-2018 model years.
The 921 is a wedge-type bulb, classified under the T15 designation, which refers to its tubular shape with a width of 15 thirty-seconds of an inch.
The wedge base design means the 921 bulb is held in place by tension from the socket itself, with no separate metal base or pins required for installation.
The 921 operates at 12 volts and 16 watts, which is consistent with standard automotive electrical systems.
The 921 bulb conforms to ANSI standards, meaning its physical and electrical specifications are regulated for consistency across manufacturers in the United States and Canada.
The T15 wedge form factor is shared by several bulb numbers in the same family, such as the 912 and 906, though those variants differ in wattage and are not direct substitutes for the 921 in this application.