Chevrolet Sonic Back Up Light Bulb Size

Additional Notes

• The Chevrolet Sonic uses the 921 bulb size for the back up light across the 2017-2020 model years.
• The 921 bulb follows the ANSI standard, which is the recognized specification framework used in the United States and Canada for automotive lighting components.
• The 921 is a wedge-type bulb, meaning it is held in place by the tension of its base rather than by a bayonet or screw fitting, which is a common design in rear lighting applications.
• The T15 designation refers to the bulb's tubular shape, with the number indicating its width in eighths of an inch, placing it in a compact size category suited for tight housing spaces.
• The 921 operates at 12 volts, consistent with the standard electrical system voltage found in conventional passenger vehicles.
• The bulb carries a 16-watt power rating, which reflects its energy draw during operation and is a typical output level for back up light functions.
• Because the same bulb size applies uniformly across all four listed model years of the Chevrolet Sonic, no year-specific fitment variation exists within this range for the back up light position.