Fiat 128 front and rear turn signal bulbs utilize 1157, 1156, and 1141 sizes depending on location and model variant. The replacement chart covers 1971 through 1979 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 1157 bulb is the most frequently specified front turn signal bulb across the Fiat 128 model range, appearing in eight of the nine model years listed, covering 1971-1972 and 1974-1979.
The 1157 is a dual-filament bulb rated at 12V with a 21W/5W output, mounted on a BAY15d bayonet base. The dual-filament design allows a single bulb to serve two lighting functions at different wattages.
The 1156 is the most consistently specified rear turn signal bulb for the Fiat 128, used across the majority of model years in that position.
The 1156 is a single-filament bulb rated at 12V and 21W, using a BA15s bayonet base. Unlike the 1157, it supports only one lighting function.
The 1157 and 1156 share the same 12V, 21W rating for their primary filament, but they are not interchangeable due to their different base types. The BAY15d base of the 1157 has offset pins, while the BA15s base of the 1156 has aligned pins.
The 1141 bulb is specified for the rear turn signal of the 1972 Fiat 128. It is a single-filament bulb rated at 12V and 21W, also using a BA15s bayonet base.
Because the 1141 and 1156 share the BA15s base type and the same 12V, 21W rating, they are physically and electrically similar, though they carry different ANSI designations.
The 1973 Fiat 128 front turn signal is specified with a 1156 rather than the 1157 used in surrounding model years, making it the only front position in the dataset to use a single-filament bulb.
All three bulb types listed are ANSI-standardized for the US and Canadian markets, indicating these specifications reflect North American fitment.