The Subaru Impreza brake light uses 7443 and 1157 bulb sizes for the specific lighting components located at the rear of the vehicle. Available data covers the period from 1993 through 2016 for the various versions of the automobile.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Subaru Impreza brake light circuit uses two distinct bulb types across its model years: the 1157 for the 1993-2001 model years and the 7443 for the 2015-2016 model years.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W high filament and a 5W low filament, which allows it to serve both brake and tail light functions within a single unit.
The 7443 is also a dual-filament bulb, housed in a T20 wedge form factor, and shares the same 12V, 21W/5W rating as the 1157, though its wedge base makes it physically incompatible with the bayonet socket used by the 1157.
Because the 1157 and 7443 use different base types, a bayonet socket and a wedge socket respectively, neither bulb is interchangeable with the other despite sharing identical wattage ratings.
The center high mount stop light on the Subaru Impreza uses T15 wedge bulbs across all listed model years, with the specific type varying between the 912 and the 921.
The 912 and 921 are both T15 wedge bulbs operating at 12V, but they differ in wattage: the 912 is rated at 12W while the 921 is rated at 16W, and the 912 is classified as a variant of the 921.
The Subaru Impreza center high mount stop light used the 912 bulb for the 1993-1997 model years, then transitioned to the 921 for 1998-2000, before returning to the 912 for the 2001 model year.
Although the 912 and 921 share the same T15 wedge base and are physically compatible in terms of socket fitment, substituting one for the other results in a difference in output due to the 4W wattage gap between them.