International 9400 front turn signal bulbs utilize 1156 size while rear turn signal bulbs use 1157 size. The replacement chart covers vehicle production spanning 1990 to 1997.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The International 9400 uses the 1156 bulb for the front turn signal across all listed model years, 1990-1997.
The 1156 is a single-filament bulb operating at 12V and 21W, fitted with a BA15s bayonet base, and recognized under ANSI standards in the United States and Canada.
The BA15s base designation indicates a single-contact bayonet fitting, which is not interchangeable with dual-contact bayonet bases used on other bulb types.
The rear turn signal on the International 9400 uses the 1157 bulb across all listed model years, 1990-1997.
The 1157 is a dual-filament bulb rated at 12V with two wattage outputs, 21W for the high-intensity filament and 5W for the low-intensity filament, also recognized under ANSI standards in the United States and Canada.
The 1157 uses a BAY15d bayonet base, which features two offset pins to ensure correct orientation during installation, preventing accidental substitution with single-contact bases.
Because the 1156 and 1157 share the same 21W primary filament rating and both use bayonet-style bases, the two types are sometimes confused, but their base configurations differ and they are not interchangeable.
The dual-filament design of the 1157 allows the rear turn signal housing to serve a combined function, with the lower-wattage filament typically used for a secondary lighting role such as a running or brake light.