Mercury Caliente front turn signal bulbs utilize 1157NA or 1034NA sizes, while rear turn signal bulbs use 1157 size. The replacement chart covers 1964 through 1967 model 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.
All three bulb types specified for the Mercury Caliente, the 1157NA, 1034NA, and 1157, share the BAY15d bayonet base and operate at 12V with a 21W/5W dual-filament configuration.
The BAY15d base is a double-contact bayonet fitting, where the two filaments serve separate functions, typically a brighter filament for the turn signal flash and a dimmer filament for a steady running or parking light.
All bulbs listed across both the front and rear turn signal positions are dual-filament types, consistent with the 21W/5W power rating shared among them.
The 1034NA is described as a variant of the 1157, meaning the two share closely related electrical and physical characteristics despite carrying different ANSI designations.
The 1157NA and 1034NA bulbs feature natural amber glass, which produces an amber light output directly from the bulb itself rather than relying on a colored lens to filter a clear light source.
The rear turn signal position on the Mercury Caliente uses the 1157 bulb across all four model years covered, 1964-1967, making it the single most consistently specified bulb in these listings.
The front turn signal position alternates between two bulb sizes depending on the model year: the 1157NA was specified for 1964 and 1967, while the 1034NA was specified for 1965-1966.
Because the 1034NA is a variant of the 1157 rather than an identical replacement, substitution between the two in front turn signal applications warrants attention to the specific year being serviced.
The 1157 used at the rear position lacks the NA suffix, indicating it has a clear glass envelope rather than the natural amber glass of the 1157NA used at the front in certain years.