Mercedes-Benz B250e Back Up Light Bulb Size

The Mercedes-Benz B250e back up light requires a bulb with the unique size 921. Data for the specific component covers the range from 2016 to 2017.

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
2016-2017	921

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

The Mercedes-Benz B250e uses the 921 bulb for its back up lights across the 2016-2017 model years.
The 921 is classified as a T15 wedge-type bulb, meaning it uses a plastic wedge base rather than a metal pin or bayonet fitting to seat into its socket.
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, indicating the bulb meets defined performance and construction criteria for those markets.
The T15 wedge form factor is shared across many automotive applications, though fitment compatibility depends on socket design and available clearance within the housing, not bulb shape alone.