International 9900i Turn Signal Bulb Size

Additional Notes

• The front turn signal on the International 9900i uses the 3157NA bulb across the 2011-2017 model years covered in the specifications.
• The 3157NA is an ANSI-standardized bulb type, meaning its physical and electrical characteristics conform to a defined North American specification used across multiple vehicle manufacturers.
• The bulb operates on a 12-volt system with a dual-wattage rating of 27W and 7W, corresponding to its two filaments, which serve separate functions such as turn signaling and parking or running light duties.
• The T25 wedge base format of the 3157NA means the bulb is retained by the pressure of its base against the socket housing rather than by a bayonet or screw mechanism.
• The "NA" suffix in the 3157NA designation indicates natural amber glass, which produces an amber-colored output directly from the glass envelope rather than relying on a colored lens or housing to filter white light.
• The 3157NA is closely related to the standard 3157 bulb but is not a direct substitute in all applications, as the amber glass of the 3157NA affects the output color in ways that a clear 3157 would not replicate when used behind a clear or non-amber lens.