International S2524 Back Up Light Bulb Size

The International S2524 back up light requires a bulb size of 1156 for proper installation and function. Data for the specified component covers the range from 1980 to 1982.

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
1980-1982	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

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Additional Notes

The 1156 is the sole bulb type listed for the back up light of the International S2524, covering model years 1980-1982.
The 1156 operates on a 12-volt circuit and draws 21 watts, placing it in the standard incandescent range for single-circuit automotive lighting applications.
The 1156 uses a single filament, which is consistent with its use in back up lights, a function that requires only one on/off state rather than variable brightness levels.
The base type for the 1156 is the BA15s bayonet mount, a single-contact design where the "s" denotes a single pin, distinguishing it from the dual-contact BA15d base used in two-filament bulbs.
The 1156 carries ANSI standardization recognized in both the United States and Canada, meaning it conforms to a defined set of electrical and physical parameters shared across compliant manufacturers.
Because the BA15s base is a single-contact bayonet, it is not interchangeable with visually similar bulbs that use a BA15d base, such as the 1157, despite the housings appearing nearly identical.