The Subaru Legacy brake light utilizes 7443 and 1157 bulb sizes according to the provided technical specifications for the lighting system. Data for the specific components covers the time range from 1990 through 2014.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Subaru Legacy uses the 7443 bulb for the brake light across the 2008-2014 model years. This bulb is a dual-filament T20 wedge type rated at 12V with a 21W high-filament and 5W low-filament output, conforming to ANSI standards for the US and Canadian markets.
The 1157 bulb serves the brake light position on the Subaru Legacy for the 1990-1999 model years. It is also a dual-filament design rated at 12V, 21W/5W, but uses a BAY15d bayonet base rather than a wedge mount, making it physically incompatible with the 7443 socket despite sharing the same wattage ratings.
Although the 7443 and 1157 share identical 21W/5W dual-filament ratings, their base types differ entirely. The 7443 uses a wedge base while the 1157 uses a BAY15d bayonet base, meaning the two bulbs are not interchangeable.
The 7440 bulb is specified for the Center High Mount Stop Light on the Subaru Legacy for the 2008-2009 model years, and for 2010 models produced up to April 2009. It is a single-filament T20 wedge bulb rated at 12V, 21W.
The 7440 and 7443 share the same T20 wedge form factor and 12V, 21W rating on their primary filament. The key difference is that the 7443 carries an additional 5W filament, which can affect socket fitment depending on the specific housing design.
The 912 bulb is used in the Center High Mount Stop Light on the Subaru Legacy for the 1990-1995 and 1992-1994 model years, as well as 1999. It is a T15 wedge bulb rated at 12V, 12W and is classified as a variant of the 921.
The 921 bulb fills the Center High Mount Stop Light position on the Subaru Legacy for the 1996-1998 model years. It is also a T15 wedge bulb but is rated at 12V, 16W, giving it a higher wattage output than the 912 despite the two sharing the same base type.
Because the 912 and 921 use the same T15 wedge base, physical installation is possible in either socket. However, their wattage ratings differ, with the 912 at 12W and the 921 at 16W, which is relevant when matching output to the original specification for a given model year.