Toyota Tercel Brake Bulb Size

Additional Notes

• The 1157 bulb is the most frequently specified brake bulb across Toyota Tercel model years, covering the standard brake light position from 1980-1997 as well as the outer brake position through most of the 1990s. It is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W high filament and 5W low filament, conforming to ANSI standards for the US and Canada.
• The 7443 is a dual-filament wedge bulb in the T20 form factor, also rated at 12V, 21W/5W, and sharing the same wattage output as the 1157. Despite identical electrical ratings, the two bulbs use physically different bases, the 7443 using a wedge-style fitting rather than a bayonet mount, which makes them non-interchangeable.
• The 921 bulb is a single-filament wedge type in the T15 form factor, rated at 12V and 16W. Its single-filament design reflects its dedicated use in the Center High Mount Stop Light, a position that requires only one brightness level rather than the dual-intensity output needed for combined brake and tail light functions.
• The 1156 bulb is a single-filament type with a BA15s bayonet base, rated at 12V and 21W. It shares the same bayonet-style mounting family as the 1157 but differs in that it carries only one filament. The BA15s base of the 1156 and the BAY15d base of the 1157 are not interchangeable, as the pin offset on the BAY15d prevents incorrect installation of a single-filament bulb in a dual-filament socket.
• The Toyota Tercel (1998) presents a mid-year fitment split for the outer brake position. Vehicles produced through December 1997 use the 1157, while those produced from December 1997 onward use the 7443, meaning two different bulb types apply to the same model year depending on production date.
• The Center High Mount Stop Light transitioned from the 1156 to the 921 between the 1990 and 1991 model years. Both are single-filament bulbs, but they differ in base type and wattage, the 1156 using a BA15s bayonet base at 21W and the 921 using a wedge base at 16W, making them physically and electrically distinct.
• All four bulb types specified across these brake light positions conform to ANSI standards applicable in the US and Canada, indicating standardized electrical and physical tolerances within their respective categories.