The International 4900 uses a 1156 bulb size for front turn signal applications and a 1157 bulb size for rear turn signal functions. The replacement chart covers 1992 through 1997 model 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 4900 uses the 1156 bulb for the front turn signal across the 1992-1997 model years.
The 1156 is a single-filament bulb operating at 12V and 21W, fitted with a BA15s bayonet base, and recognized under ANSI standards in both the United States and Canada.
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 4900 uses the 1157 bulb across the same 1992-1997 model years.
The 1157 is a dual-filament bulb rated at 12V with two wattage outputs, 21W for the turn signal filament and 5W for the secondary filament, and it uses a BAY15d bayonet base.
The BAY15d base on the 1157 features offset pins that prevent incorrect insertion, a design distinction from the symmetrical BA15s base used on the 1156.
Although both the 1156 and 1157 share a 12V operating voltage and a 21W primary filament rating, their base types differ, making them physically non-interchangeable despite the similarity in electrical output.
The front and rear turn signal positions on the International 4900 require different bulb types, with the single-filament 1156 at the front and the dual-filament 1157 at the rear.