The International 4600 front turn signal bulb uses a 1156 size, while the rear turn signal bulb uses a 1157 size. The replacement chart covers 1992 through 1995 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 4600 uses the 1156 bulb for the front turn signal across the 1992-1995 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 features a single contact pin, which physically prevents substitution with dual-filament bulbs that use a different base configuration.
The rear turn signal on the 1992-1995 International 4600 takes the 1157 bulb.
The 1157 is an ANSI-standard dual-filament bulb rated at 12V with a 21W primary filament and a 5W secondary filament, mounted on a BAY15d bayonet base.
The BAY15d base uses two offset contact pins, a design that distinguishes it from the BA15s base and prevents accidental cross-installation between the 1156 and 1157.
Although the 1156 and 1157 share the same 21W rating on their primary filament and both operate on a 12V system, they are not interchangeable due to differing base types and filament configurations.
Both the 1156 and 1157 are recognized ANSI standards applicable in the United States and Canada, indicating broad availability across North American markets.