Mercedes-Benz B Electric Drive Back Up Light Bulb Size

The Mercedes-Benz B Electric Drive back up light requires a bulb size of 921 for the rear lighting system. Data for the specific bulb requirements covers the period from 2014 to 2015.

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
2014-2015	921

Bulb Specifications

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

Other Locations

Additional Notes

The 921 bulb is the specified back up light bulb size for the Mercedes-Benz B Electric Drive across the 2014-2015 model years.
The 921 is a wedge-type bulb, classified under the T15 form factor, which refers to its tubular shape measuring 15 eighths of an inch in width.
Wedge bulbs use a plastic base with two wire contacts that grip the socket directly, eliminating the need for a separate metal base or pins.
The 921 operates at 12 volts and 16 watts, which is consistent with standard automotive low-voltage electrical systems.
The 921 designation follows the ANSI standardization system used in the United States and Canada, meaning bulbs from different manufacturers carrying the same number share identical electrical and physical specifications.
Because the 921 is an ANSI-standardized part, it is interchangeable across any vehicle application that lists the same bulb number, provided the socket type is compatible.