Mercury Capri front turn signal bulbs utilize 1156, 1157, or 1157NA sizes, while rear turn signal bulbs use 1156 or 1157 sizes depending on model year. The replacement chart covers 1970 through 1994 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Mercury Capri uses two distinct turn signal bulb types across its production span: the 1156 and the 1157, both of which are ANSI-standardized bulbs rated for 12 volts and recognized across the United States and Canada.
The 1157 is a dual-filament bulb mounted on a BAY15d bayonet base, rated at 21W for its high-intensity filament and 5W for its low-intensity filament, allowing it to serve both signaling and parking light functions within a single housing.
The 1156 is a single-filament bulb mounted on a BA15s bayonet base, rated at 21W, and is dedicated solely to a single lighting function rather than the combined role of the 1157.
The BA15s base of the 1156 and the BAY15d base of the 1157 are physically incompatible with each other. The offset pins on the BAY15d base prevent a 1157 from seating into a socket designed for the 1156, and vice versa, making cross-substitution between these two types impossible without modification.
The Mercury Capri (1991-1994) uses the 1156 bulb for both the front and rear turn signals, representing a shift from the 1157 used in earlier model years.
The 1157 bulb is specified for both front and rear turn signals across the 1970-1986 model years, with the sole exception of the 1984 front turn signal, which uses the 1157NA variant.
The 1157NA is a natural amber glass version of the standard 1157, sharing the same BAY15d base, 12V rating, and 21W/5W dual-filament configuration. The amber glass tints the emitted light without relying on a colored lens or bulb coating.
Because the 1157NA shares its base type and electrical ratings with the standard 1157, the two are physically interchangeable in terms of socket fitment, though the amber tint of the 1157NA will affect the color output of the light.
The 1157 is the most widely specified bulb across the Capri turn signal data, appearing in the front and rear positions across the majority of model years covered in the specifications.