The Acura ILX back up light requires a 921 bulb size for proper installation and function within the rear lighting assembly. Data for the specified component covers the range from 2013 to 2022.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 921 is the sole bulb type listed across all back up light positions for the Acura ILX, covering the 2013-2022 model years as well as the Outer Back Up Light position on the 2017-2018 models.
The 921 is an ANSI-standardized bulb recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical parameters shared across manufacturers.
The 921 uses a wedge-style base, classified as T15, which refers to a tubular bulb body approximately 15 eighths of an inch wide. The wedge base design requires no separate metal socket pins, as the glass envelope itself acts as the retaining element.
The 921 operates at 12 volts and 16 watts, which are standard values for automotive reverse lighting in low-voltage DC electrical systems.
The T15 wedge base format is shared with several other bulb types in the same family, such as the 912 and 906, which differ primarily in wattage. Substituting a different wattage variant in place of the 921 risks incorrect light output or electrical load mismatches.
The Outer Back Up Light designation on the 2017-2018 ILX indicates a physically distinct lamp position from the general back up light, though both positions share the same 921 specification.