The Nissan D21 brake light requires a 1157 bulb size for proper installation and function within the rear lighting assembly. Provided specifications cover a production range from 1986 through 1994.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Nissan D21 uses the 1157 bulb for brake lighting across the 1986-1994 model years.
The 1157 is a dual-filament bulb, meaning it serves two lighting functions within a single unit. In brake light applications, the higher 21W filament activates under braking, while the lower 5W filament typically handles tail light or parking light duty.
The 1157 operates on a 12V system and uses a BAY15d bayonet base, a two-pin offset base design that prevents incorrect installation by ensuring the bulb can only be seated in one orientation.
The Center High Mount Stop Light on the Nissan D21 uses the 921 bulb for the 1989-1994 model years.
The 921 is a single-filament wedge-type bulb in the T15 form factor, rated at 12V and 16W. Unlike the 1157, it has no secondary filament and is dedicated solely to stop light function in this application.
The 921 uses a wedge base rather than a bayonet base, making it physically incompatible with the socket designed for the 1157. The two bulb types are not interchangeable despite both operating at 12V.
Both the 1157 and 921 conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and photometric performance across manufacturers.
The difference in wattage between the two bulbs, 21W for the primary filament of the 1157 versus 16W for the 921, reflects the distinct roles of the main brake lights and the center high mount stop light in the overall braking signal system.