The Mazda RX-7 brake light utilizes a specific 1157 bulb size for illumination across various production versions. Available data covers a continuous span from 1979 through 1995.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mazda RX-7 uses the 1157 bulb for the brake light position across all listed model years from 1979-1995, making it the most consistently specified bulb in these fitment records.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output and a BAY15d bayonet base. The dual-filament design allows a single bulb to serve both the brake light and tail light functions at different wattages.
The BAY15d bayonet base on the 1157 features two offset pins, which physically prevents incorrect installation of a single-filament bulb in its place. A 1156 bulb, which shares a similar appearance but uses a BA15s single-pin base, is not a direct substitute.
The Center High Mount Stop Light (CHMSL) on the RX-7 uses a different bulb than the main brake light position, and the specification for that position changed between the 1991 and 1993 model years.
The Mazda RX-7 CHMSL for 1988-1991 is specified with the 1156 bulb, a single-filament 12V, 21W bulb with a BA15s bayonet base. Because the CHMSL serves only one function, a single-filament bulb is sufficient for that application.
The CHMSL specification for the 1993-1995 RX-7 shifted to the 921 bulb, a wedge-type T15 bulb rated at 12V and 16W. The wedge base design requires no locking pins and is retained by the socket's tension alone.
The 921 wedge bulb used in the 1993-1995 CHMSL operates at a lower wattage (16W) than the 1156 it replaced in earlier model years (21W), reflecting a difference in socket and housing design between the two generations.
All three bulb types specified across these records, the 1157, 921, and 1156, conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical tolerances across all three.
The 1156 and 1157 bulbs share the same 21W high-output filament rating, but their base types are mechanically incompatible with each other's sockets, making cross-substitution between the CHMSL and main brake light positions on applicable model years physically impractical.
The 1992 model year does not have a listed entry in either the brake light or CHMSL specifications for the RX-7.