BMW 650i Gran Coupe Back Up Light Bulb Size

Additional Notes

• The BMW 650i Gran Coupe uses the 921 bulb for the back up light position across all model years from 2013-2019.
• The 921 is a wedge-type bulb, classified under the T15 designation, which refers to its tubular glass envelope measuring 15 thirty-seconds of an inch in width.
• Wedge bulbs are named for their base design, where the glass envelope itself is pinched at the bottom to form a wedge shape that holds the bulb in place without a separate metal base.
• The 921 operates at 12 volts and draws 16 watts, which is consistent with standard automotive low-current accessory circuits.
• The 921 carries ANSI standardization, meaning its physical and electrical specifications are governed by a recognized industry standard applicable in both the United States and Canada.
• Because the 921 is an ANSI-standardized part, it is produced by multiple manufacturers and is widely available as a direct replacement without modification to the socket or wiring.
• The T15 wedge format is a common fitment in reverse light applications across many vehicle platforms, though substitution with physically similar bulbs of differing wattage ratings can affect circuit performance or trigger fault warnings in vehicles with bulb monitoring systems.