Mitsubishi Fuso FM-SP Back Up Light Bulb Size

The Mitsubishi Fuso FM-SP back up light requires bulb size 1156 or P21W depending on the specific application. Data for the provided bulb sizes covers the range from 1996 to 1998.

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
1996-1998	1156

Bulb Specifications

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

Other Locations

Additional Notes

The 1156 is the sole bulb type listed for the Mitsubishi Fuso FM-SP back up light across the 1996-1998 model years.
The 1156 is an ANSI-standardized bulb used in the United States and Canada, meaning it conforms to a defined set of electrical and physical specifications recognized across North American markets.
It operates on a 12-volt electrical system and draws 21 watts, which is typical of incandescent single-filament automotive bulbs used in non-lighting signal applications such as reverse lights.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a single-contact bayonet fitting with a 15mm base width. The single-contact design corresponds directly to its single-filament construction.
Because the 1156 carries only one filament, it serves functions requiring a single on/off output, making it suited for back up lights, which operate independently without a secondary brightness level.
The BA15s base is not interchangeable with the BA15d base, which is a dual-contact variant. Substituting a dual-contact bulb into a single-contact socket would result in improper fitment.