The Mercury Tracer brake light utilizes 3157, 2458, and 1157 bulb sizes depending on the specific version of the vehicle. Data for the bulb sizes covers the period from 1988 through 1999.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercury Tracer brake lights use two ANSI-standard dual-filament bulb types across its model years: the 3157 (T25 wedge, 12V, 27W/7W) for 1997-1999, and the 1157 (BAY15d bayonet base, 12V, 21W/5W) for 1988-1989 and 1991-1992.
The 3157 and 1157 are both dual-filament bulbs, meaning each contains a higher-wattage filament for braking and a lower-wattage filament for running lights. Despite this shared function, the two bulbs are not interchangeable due to different base types and wattage ratings.
The 3157 uses a wedge-style T25 base, while the 1157 uses a BAY15d bayonet base. These base configurations are physically incompatible with each other's sockets.
The center high mount stop light (CHMSL) on the Mercury Tracer uses three different bulb types depending on the model year, reflecting a broader range of variation than the standard brake lights.
The 921 wedge bulb (T15, 12V, 16W) is a single-filament ANSI-standard bulb used in the CHMSL for 1992 and 1997-1999. As a dedicated stop light position, single-filament construction is sufficient for this application.
The 1141 is a single-filament bulb with a BA15s bayonet base rated at 12V and 21W, used in the CHMSL for 1989-1991. Although the 1141 and P21W share the same BA15s base and 12V/21W rating, one is an ANSI-standard bulb and the other follows the ECE standard.
The 1988 Mercury Tracer CHMSL specifies the P21W, an ECE-standard single-filament signalling bulb with a BA15s bayonet base rated at 12V and 21W. The ECE standard is used primarily in European and international markets, making this specification notable for a North American vehicle.
The physical similarity between the 1141 and P21W, both using a BA15s base at 12V/21W, means cross-compatibility is a practical consideration, though the differing regulatory standards (ANSI vs. ECE) represent a technical distinction between the two bulbs.
The 921 and 1141 are not interchangeable despite both being single-filament ANSI bulbs. The 921 uses a wedge base while the 1141 uses a BA15s bayonet base, and their wattage ratings also differ at 16W and 21W respectively.
Across all listed positions and years, the Mercury Tracer brake lighting system draws exclusively from 12V bulbs, consistent with standard 12-volt automotive electrical systems.