International 4900 Back Up Light Bulb Size

The International 4900 back up light requires a 1156 bulb size for proper installation and function within the specified lighting assembly. Data provided for the bulb specifications covers the range from 1992 to 1997.

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
1992-1997	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 specified for the backup light across all listed model years of the International 4900.
The International 4900 uses the 1156 bulb for its backup light across the 1992-1997 model years.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, which is consistent with its dedicated backup light application.
The 1156 operates at 12 volts and 21 watts, placing it in the standard range for incandescent automotive signal and utility lighting.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a single-contact bayonet fitting with a 15mm base width.
The 1156 conforms to ANSI standards and is recognized in both the United States and Canada, reflecting its use in North American vehicle markets.
The BA15s base of the 1156 is a single-contact design, which is electrically distinct from the BA15d double-contact base used on some visually similar bulbs; substituting one for the other is not compatible.
The 1156 is sometimes referenced alongside the 1157, which shares a similar physical form but carries a dual-filament design and a BA15d base, making the two types non-interchangeable despite their outward resemblance.