International 7500 front turn signal bulbs use 3157NA size while rear turn signal bulbs use 3157 size. The replacement chart covers 2008 to 2017 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The International 7500 uses the 3157NA for its front turn signal across the 2008-2017 model years.
The 3157NA is a dual-filament T25 wedge bulb rated at 12V with a 27W high filament and a 7W low filament, and it features natural amber-tinted glass.
The natural amber glass of the 3157NA produces an amber output without relying on a colored lens, which is the functional distinction between it and the clear-glass 3157.
The rear turn signal on the International 7500 uses the standard 3157 across the same 2008-2017 span.
The 3157 shares the same T25 wedge base, 12V operating voltage, and 27W/7W dual-filament configuration as the 3157NA, differing only in glass color.
Both the 3157 and 3157NA conform to ANSI standards applicable in the United States and Canada.
The dual-filament design of both bulbs serves two independent circuits within a single housing, with the higher-wattage filament typically assigned to the turn signal function and the lower-wattage filament to a secondary function such as parking or running light.
Because the 3157 and 3157NA share the same base and electrical ratings, they are physically interchangeable, but substituting a clear 3157 for the 3157NA at the front position may affect amber output compliance if the lens itself is not amber-tinted.