International 4300LP front turn signal uses 3157NA bulb size while rear turn signal uses 3157 bulb size. Replacement chart covers 2011 to 2018 vehicle production years with bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The International 4300LP uses the 3157NA bulb for the front turn signal across all listed model years, 2011-2018.
The rear turn signal on this vehicle uses the 3157 bulb across the same 2011-2018 model year range.
Both the 3157NA and 3157 are ANSI-standardized dual-filament T25 wedge bulbs rated at 12V with a 27W high filament and 7W low filament, making them functionally identical in electrical terms.
The sole distinction between the 3157NA and the 3157 is the natural amber glass envelope of the 3157NA, which produces an amber-colored output without relying on an amber lens housing.
Because the front position uses the 3157NA and the rear uses the clear 3157, the two bulbs are not interchangeable between positions without affecting the color output of the turn signal.
The dual-filament design of both bulbs allows a single socket to serve two lighting functions, typically combining a higher-wattage turn or brake function with a lower-wattage running or parking function.
The T25 wedge base format means these bulbs seat directly into a wedge-style socket without a separate metal base, which is a common socket type in commercial vehicle lighting applications.