Toyota Avalon Brake Bulb Size

Additional Notes

• The Toyota Avalon brake light specifications cover three distinct bulb types across its model years: the 7440, 7443, 1157, and 921. The 7443 is by far the most frequently specified bulb across the listed positions and years.
• The 7443 is a dual-filament T20 wedge bulb rated at 12V with a 21W high filament and a 5W low filament. Its dual-filament design allows it to serve both brake and running light functions from a single socket.
• The 7440 is a single-filament T20 wedge bulb rated at 12V, 21W. Although it shares the same T20 wedge base form factor as the 7443, it lacks a second filament, which makes the two bulbs functionally non-interchangeable in sockets that require dual-filament operation.
• The 1157 is a dual-filament bulb rated at 12V, 21W/5W, but it uses a BAY15d bayonet base rather than a wedge base. This base type is physically incompatible with T20 wedge sockets, so the 1157 cannot be substituted for a 7443 or 7440 without an adapter or socket change.
• The 921 is a single-filament T15 wedge bulb rated at 12V, 16W. It is a smaller form factor than the T20 bulbs and is specified exclusively for the Center High Mount Stop Light position in the Toyota Avalon.
• The Toyota Avalon (1995-1997) used the 1157 bayonet-base bulb for its standard brake position. Starting with the 1998 model year, production units built from September 1997 onward transitioned to the 7443 T20 wedge bulb, representing a base-type change mid-cycle.
• A similar mid-year fitment note applies to the Outer Brake position on the 2005 Toyota Avalon, where the 7443 bulb applies only to units produced from January 2005 onward. Units produced before that date are not addressed in the specifications for that position.
• The standard brake position on the Toyota Avalon (2011-2012) specifies the 7440 single-filament bulb, while the Outer Brake position for those same years specifies the 7443 dual-filament bulb. Both positions use T20 wedge bases, but the filament count differs between them.
• The Center High Mount Stop Light position on the Toyota Avalon uses the 921 bulb for model years 1995-2004. This position is not listed in the specifications for model years 2005 and later.
• All four bulb types listed in the specifications conform to ANSI standards applicable to the US and Canadian markets, indicating they are standardized sizes rather than proprietary or region-specific components.