International S2155 front turn signal bulbs use 1156 size while rear turn signal bulbs use 1157 size. The replacement chart covers 1984 to 1989 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 International S2155 uses the 1156 bulb for the front turn signal across all listed model years, 1984-1989.
The 1156 is an ANSI-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base.
The rear turn signal on the International S2155 uses the 1157 bulb across the same 1984-1989 model year range.
The 1157 is an ANSI-standard dual-filament bulb rated at 12V with filaments drawing 21W and 5W respectively, fitted with a BAY15d bayonet base.
The front and rear turn signals on the S2155 are not interchangeable. The 1156 uses a BA15s single-contact base, while the 1157 uses a BAY15d dual-contact base, and the two base types are physically distinct.
Both the 1156 and 1157 are recognized ANSI standards applicable in the United States and Canada.
The dual-filament design of the 1157 allows it to serve two lighting functions at different wattages, which is a characteristic that distinguishes it from the single-filament 1156 used at the front.