The Subaru Standard brake light utilizes 1157, 1073, and P21W bulb sizes depending on the specific production period for the vehicle. Data for the components spans from 1979 through 1987.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Subaru Standard uses the 1157 bulb for brake lighting across the majority of its specified model years, covering 1979 and 1982-1987.
The 1157 is a dual-filament bulb rated at 12V with a 21W/5W output, mounted on a BAY15d bayonet base, conforming to the ANSI standard used in the United States and Canada.
Its dual-filament design allows a single bulb to serve two functions, typically combining a lower-intensity running light with a higher-intensity brake signal within the same housing.
The 1981 Subaru Standard uses the 1073 bulb for the brake light position, which differs from the 1157 used in surrounding years.
The 1073 is a single-filament bulb rated at 12V and 13W, also using a BA15s bayonet base, and is classified as a lower-wattage variant of the 1156 under the ANSI standard.
The 1980 Subaru Standard uses the P21W bulb, an ECE-standard single-filament signalling bulb rated at 12V and 21W, also fitted with a BA15s bayonet base.
Although the 1073 and P21W share the same BA15s base, their differing wattage ratings and regulatory standards mean they are not direct substitutes for one another.
The Center High Mount Stop Light on the Subaru Standard for 1985-1987 uses the 921 bulb, a wedge-type T15 bulb rated at 12V and 16W under the ANSI standard.
The 921 wedge base is physically incompatible with the BAY15d and BA15s bayonet bases used in the main brake light positions, making cross-position substitution impossible without modification.
The P21W used in the 1980 model year follows ECE rather than ANSI standards, which reflects a different regional specification compared to the ANSI-rated bulbs used in all other listed years.