The Mazda Miata brake light uses 1157 and 7443 bulb sizes according to the provided specifications for the rear lighting components. Data for the specific bulbs covers the range from 1990 through 2005.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mazda Miata uses two distinct brake bulb types across its model years: the 7443 for 1999-2005 and the 1157 for 1990-1997, both rated at 12V with a 21W/5W dual-filament configuration.
The 7443 is a dual-filament wedge bulb in the T20 form factor, conforming to ANSI standards for the US and Canadian markets. Its wedge-style base differs fundamentally from a bayonet-style fitting.
The 1157 shares the same 12V, 21W/5W electrical rating as the 7443 but uses a BAY15d bayonet base rather than a wedge mount, making the two bulbs physically non-interchangeable despite identical wattage ratings.
Because the 7443 and 1157 use different base types, a direct substitution between the two brake bulb generations is not possible without a socket adapter or wiring modification.
The center high mount stop light (CHMSL) on the Miata follows a parallel generational split: the 1156 is specified for 1999-2005, while the 921 is specified for 1990-1997.
The 1156 is a single-filament bulb with a BA15s bayonet base rated at 12V and 21W. Its single-filament design contrasts with the dual-filament 1157 used in the main brake lights of the same era, and the two bulbs are not interchangeable despite sharing a similar bayonet base family.
The 921 is a single-filament wedge bulb in the T15 form factor, rated at 12V and 16W. Its lower wattage relative to the 1156 reflects its role in the CHMSL rather than a primary brake light position.
The BA15s base of the 1156 and the BAY15d base of the 1157 are both bayonet-style fittings, but the offset pins on the BAY15d prevent a 1156 from seating correctly in a 1157 socket, ruling out cross-substitution.