Plymouth GTX front and rear turn signal bulbs utilize 1157, 1034, and 1034NA bulb sizes depending on location and model variation. The replacement chart covers 1967 through 1971 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Plymouth GTX uses two distinct bulb types across its turn signal specifications: the 1157 and the 1034, along with a natural amber variant of the 1034 designated 1034NA.
All three bulb types share the BAY15d bayonet base and operate at 12V with a dual-filament configuration rated at 21W and 5W, placing them within the same general family of ANSI-standard bulbs.
The 1034 and 1034NA are both classified as variants of the 1157, meaning they share the same base type and voltage rating but are not identical replacements for one another.
The 1034NA carries a natural amber glass envelope, which distinguishes it physically from the clear-glass 1034 despite otherwise identical electrical specifications.
The Plymouth GTX (1969-1971) uses the 1157 bulb in both the front and rear turn signal positions.
The 1968 GTX uses the 1034 bulb in both the front and rear turn signal positions, representing a direct parallel to the 1157 fitment pattern of later model years.
The 1967 front turn signal position specifies the 1034NA, while the rear position for the same year specifies the standard 1034, meaning the two positions are not interchangeable for that model year.
Because the 1034 and 1157 share the BAY15d base, physical installation may be possible across types, but they carry separate ANSI designations and are not listed as interchangeable within these specifications.