The Subaru GL-10 brake light requires a 1157 bulb size for proper installation and function. Data for the specific component covers the period from 1985 through 1989.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Subaru GL-10 uses the 1157 bulb for brake lighting across the 1985-1989 model years.
The 1157 is a dual-filament bulb rated at 12V with a 21W/5W output, meaning its two filaments serve separate functions at different wattages within the same housing.
The 1157 uses a BAY15d bayonet base, a two-pin offset design that prevents incorrect installation by ensuring only one rotational orientation fits the socket.
The center high mount stop light on the GL-10 uses the 1156 bulb for the 1985-1989 model years, but only on trims equipped with halogen capsule headlamps.
The 1156 is a single-filament bulb rated at 12V and 21W, carrying the same voltage and primary wattage as the 1157 but without a secondary filament.
The 1156 uses a BA15s bayonet base, a single-pin design that is not interchangeable with the BAY15d base found on the 1157, despite the two bulbs sharing a similar physical profile.
Both the 1157 and 1156 are ANSI-standardized bulb types recognized across the United States and Canada, placing them within a widely distributed sizing system.
The fitment of the 1156 to the center high mount stop light is conditional, as the halogen capsule headlamp configuration on the Subaru GL-10 determines which bulb applies to that position.