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	US Type	EU Type	Shop
2012-2017	1156	P21W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W	Check Price

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.