International S1654 uses 1156 bulb size for front turn signal and 1157 bulb size for rear turn signal applications. The replacement chart covers 1984 through 1989 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 International S1654 uses the 1156 bulb for the front turn signal across all listed model years, spanning 1984-1989.
The 1156 is an ANSI-standard single-filament bulb rated at 12V and 21W, fitted with a BA15s bayonet base.
The BA15s base designation indicates a single-contact bayonet mount, which is not interchangeable with dual-contact bayonet bases.
The rear turn signal on the International S1654 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 a 21W primary filament and a 5W secondary filament, fitted with a BAY15d bayonet base.
The BAY15d base on the 1157 features offset locating pins, which prevents it from being seated in a BA15s socket designed for the 1156.
Although both the 1156 and 1157 share a 12V operating voltage and a 21W primary wattage, their differing base types and filament configurations make them non-interchangeable between front and rear positions.
The dual-filament design of the 1157 allows it to serve both a turn signal function and a secondary running or brake light function within a single housing, which accounts for its use at the rear.
Both bulb types conform to ANSI standards applicable in the United States and Canada, indicating standardized electrical and physical specifications across manufacturers.