The Subaru Outback brake light uses 912, 7440, and 7443 bulb sizes depending on the specific version required for the vehicle. Data for the bulb sizes covers the range from 2008 to 2021.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 7440 bulb is the most frequently specified brake bulb across the Subaru Outback data provided, covering model years 2010-2014 for the brake light position.
The 7440 is a single-filament T20 wedge bulb rated at 12V and 21W, conforming to ANSI standards applicable in both the United States and Canada.
The 7443 bulb shares the same T20 wedge form factor and 12V/21W primary rating as the 7440, but adds a second filament rated at 5W, making the two bulbs physically similar yet functionally distinct.
Because the 7440 and 7443 share the T20 wedge base, physical fitment between the two is possible in some sockets, but substituting a single-filament 7440 where a dual-filament 7443 is specified would result in the loss of one lighting function.
The Subaru Outback (2008-2009) uses the 7443 dual-filament bulb for the brake light position, indicating those model years rely on a single bulb to serve two separate circuit functions through its dual filaments.
The 2009-2008 Center High Mount Stop Light on the Subaru Outback specifies the 7440 single-filament bulb, a different specification from the main brake light position used in those same years.
The 912 bulb specified for the 2021 Outback brake light is a T15 wedge type rated at 12V and 12W, a notably lower wattage than the T20 bulbs specified for earlier model years.
The 912 is described as a variant of the 921 bulb, meaning the two share close electrical and physical characteristics, though they are not identical and are not listed as interchangeable within these specifications.
The T15 and T20 designations refer to the tubular bulb body width, with T15 indicating a narrower profile than T20, which is relevant to socket compatibility when servicing different Outback model years.