Toyota Avalon back up light bulb sizes include 921, 1156, and 3057 bulb configurations for inner and outer positions. The replacement chart covers vehicle production from 1995 to 2019 with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Toyota Avalon back up light uses the 921 bulb across the widest range of model years in these specifications, covering the standard back up light position from 1998 through 2019, with the exception of 1995-1997, which use the 1156 bulb instead.
The 921 is a T15 wedge-base bulb rated at 12V and 16W. The wedge base means the glass envelope itself acts as the retention mechanism, with no separate metal base or bayonet pins.
The 1156 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 21W. The BA15s base uses a single locating pin, distinguishing it from dual-pin bayonet variants. It draws more wattage than the 921.
The 3057 is a dual-filament T25 wedge bulb rated at 12V with filaments at 27W and 7W. Its presence in a back up light position means only one filament is active for that function, while the second filament serves a separate circuit within the same housing.
The inner back up light on the Toyota Avalon used the 921 bulb from 2000 through 2004, then transitioned to the 3057 starting with the 2005 model year from January 2005 onward, continuing through 2012.
The inner back up light returned to the 921 bulb for the 2013 model year, specifically from October 2012 onward, and continued with the 921 through 2018. This mid-year production date indicates a running change during the 2013 model year rather than a clean model-year boundary.
The 921 and 3057 are not directly interchangeable despite both using wedge bases. The T15 and T25 designations reflect different physical envelope sizes, and the 3057 carries a dual-filament configuration that the 921 does not share.
The outer back up light on the Avalon used the 1156 bulb for 1995-1997 model years, with the 1995 application noted as starting from September 1994, indicating an early production start date for that model year.
The 1156 and 921 are not interchangeable. The 1156 uses a BA15s bayonet base while the 921 uses a wedge base, making them physically incompatible with each other's sockets regardless of voltage rating.
Mid-year production qualifiers appear at several points in these specifications, including the 2013 inner back up light (from October 2012), the 2005 inner back up light (from January 2005), the 1998 outer back up light (from September 1997), and the 1995 outer back up light (from September 1994), indicating that bulb fitment for those years is production-date dependent.