Freightliner Cascadia Stepwell Bulb Size

The Freightliner Cascadia stepwell light requires a 12961 bulb size for proper illumination of the vehicle entrance area. Provided information covers the specific time period from 2008 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
2008-2017	12961

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961

Other Locations

Additional Notes

The Freightliner Cascadia stepwell position uses the 12961 bulb across all listed model years from 2008-2017, with no variation in fitment throughout that period.
The 12961 is a Philips part number designating a miniature wedge bulb in the T10 form factor, which refers to a tubular bulb body approximately 10 millimeters wide.
The bulb operates on a 12-volt electrical system and draws 5 watts, placing it in the low-wattage range typical of interior and courtesy lighting applications.
The W2.1x9.5d base type is a wedge-style base, meaning the bulb is held in its socket by the tension of the base itself rather than by a bayonet or screw mechanism.
T10 wedge bulbs with the W2.1x9.5d base are a widely standardized format, and the 12961 is interchangeable with other T10 wedge bulbs sharing the same voltage, wattage, and base specification.
Because the stepwell bulb serves a functional safety role in illuminating entry and exit points, substitutions with bulbs of differing wattage or base type risk improper fit or inadequate light output.