Freightliner 108SD Roof Marker Bulb Size

The Freightliner 108SD roof marker requires a 193 bulb size for proper installation and function. Data for 193 bulbs covers the range from 2012 through 2013.

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
2012-2013	193

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	193

Other Locations

Additional Notes

The 193 bulb follows the ANSI standard recognized in both the United States and Canada, classifying it as a miniature wedge type in the T10 form factor operating at 12 volts and 3.78 watts.
The T10 wedge base design means the bulb is held in place by the tension of its base contacts rather than a bayonet or screw mechanism, which is a common trait among low-wattage marker and clearance lamp applications.
The Freightliner 108SD uses the 193 bulb for roof marker fitment across the 2012-2013 model years, making cross-year parts interchangeability straightforward within that range.
At 3.78 watts, the 193 is a low-draw bulb, consistent with its role as a marker lamp rather than a primary illumination source.