International S1753 front turn signal bulbs use 1156 size while rear turn signal bulbs use 1157 size. The replacement chart covers vehicle production spanning 1984 to 1989.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The International S1753 uses the 1156 bulb for the front turn signal across the 1984-1989 model years.
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 S1753 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/5W output, fitted with a BAY15d bayonet base.
The dual-filament design of the 1157 allows it to serve two lighting functions within a single housing, typically combining turn signal and running light operation.
The BAY15d base on the 1157 uses offset pins to prevent incorrect installation, and it is not compatible with the BA15s socket used by the 1156.
Both the 1156 and 1157 are recognized under ANSI standards applicable in the United States and Canada, indicating standardized physical and electrical specifications across manufacturers.
Although both bulbs share a 12V operating voltage and a 21W turn signal filament rating, the differing base types mean the front and rear positions require distinct, non-interchangeable bulbs.