Buick Envision Back Up Light Bulb Size

Additional Notes

• The 921 bulb is the sole back up light bulb size listed for the Buick Envision across the 2016-2023 model years.
• The 921 bulb follows the ANSI standard, which is the recognized specification body for the United States and Canada, meaning the bulb conforms to a defined set of electrical and physical parameters for those markets.
• The 921 uses a wedge-style base, designated T15, which refers to a tubular bulb body approximately 15 eighths of an inch wide that is held in its socket by the tension of the base contacts rather than by a bayonet or screw fitting.
• The bulb operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles.
• The 921 is rated at 16 watts, placing it in the range typical for back up lighting applications where adequate illumination behind the vehicle is required without excessive current draw.
• Because the 921 appears uniformly across all listed model years of the Buick Envision, no year-specific fitment variation exists within this part category for the 2016-2023 range.
• The wedge base design of the T15 means the 921 is not interchangeable with bayonet-base or screw-base bulb types, even when voltage and wattage ratings may otherwise match.