The Subaru Justy brake light requires a 1157 bulb size for proper operation and visibility. Data provided for the specific component covers the range from 1987 to 1994.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Subaru Justy uses the 1157 bulb for its brake lights across the full 1987-1994 model range.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output, mounted on a BAY15d bayonet base. The dual-filament design allows a single bulb to serve both brake and tail light functions at different brightness levels.
The BAY15d base on the 1157 features two offset pins, which physically prevents substitution with single-filament bulbs that share a visually similar base style.
The center high mount stop light on the Subaru Justy transitioned from the P21W bulb in 1987-1988 to the 1003 bulb in 1989-1994.
The 1003 and P21W share the same BA15s bayonet base and identical 12V, 21W electrical ratings, making them functionally equivalent in terms of output and socket fitment.
Despite their physical and electrical compatibility, the 1003 follows the ANSI standard used in the United States and Canada, while the P21W follows the ECE standard used in Europe and internationally. The two designations reflect regional classification systems rather than technical differences.
The brake light circuit uses the 1157, which carries a BAY15d base, while the center high mount stop light uses either the 1003 or P21W, both of which carry a BA15s base. These two base types are not interchangeable between the two circuits.