International 4400 Back Up Light Bulb Size

The International 4400 back up light utilizes a 3157 bulb size for the specified lighting component. Data for the bulb requirements spans the range from 2011 to 2018.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2011-2018	3157

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	3157

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Additional Notes

The International 4400 uses the 3157 bulb for its back up light across the 2011-2018 model years.
The 3157 is an ANSI-standardized bulb type, meaning its specifications are governed by a formal industry standard recognized in both the United States and Canada.
The 3157 is a dual-filament bulb, meaning it contains two separate filaments within a single housing, each operating at a different wattage.
The two filaments in the 3157 operate at 27W and 7W respectively, with the higher-wattage filament typically serving the primary function and the lower-wattage filament serving a secondary role.
The 3157 carries a T25 wedge-style designation, referring to its body shape and base type, which determines physical fitment into the socket.
The 3157 is rated for 12V electrical systems, consistent with the standard voltage architecture found in commercial trucks such as the International 4400.
Because the 3157 is a dual-filament bulb, substituting it with a single-filament equivalent would result in the loss of one lighting function, making filament count a critical factor in replacement selection.
The T25 wedge base is not interchangeable with bayonet or indexed-pin base types, so socket compatibility must be confirmed before any replacement bulb is installed.