Freightliner 108SD Back Up Light Bulb Size

The Freightliner 108SD back up light utilizes a 1156 bulb size for illumination purposes. Available data for the specified component covers the period from 2012 through 2017.

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
2012-2017	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 Freightliner 108SD uses the 1156 bulb for its back up light across the 2012-2017 model years.
The 1156 is an ANSI-standardized bulb type, meaning its specifications are governed by a recognized industry standard shared across the United States and Canada.
The 1156 operates on a single filament, which distinguishes it from dual-filament variants such as the 1157, and dedicates its output to a single lighting function.
The bulb uses a BA15s bayonet base, where "BA15s" denotes a bayonet fitting with a 15mm base width and a single contact pin, requiring a matching socket for proper installation.
The 1156 is rated at 12 volts and 21 watts, placing it within the standard low-voltage electrical range typical of automotive and commercial vehicle systems.
Because the 1156 and 1157 share the same BA15s base width, physical fitment into a 1157 socket is possible, but the single-contact pin of the 1156 is not electrically compatible with the dual-contact configuration of a 1157 socket.