Freightliner Cascadia Side Marker Bulb Size

Additional Notes

• The Freightliner Cascadia uses the 4157NA bulb for the front side marker position across all listed model years from 2008-2017, indicating a consistent fitment specification throughout that period.
• The 4157NA is an ANSI-standardized bulb, meaning its specifications conform to a recognized North American standard applicable in both the United States and Canada.
• The bulb operates on a 12-volt system and carries a dual-wattage rating of 27W and 7W, which corresponds to its dual-filament construction. The higher wattage filament typically serves the turn signal function, while the lower wattage filament serves the marker or parking light function.
• The T25 designation refers to the bulb's envelope size, expressed in eighths of an inch, placing it in a mid-range size category common to automotive signal lighting applications.
• The natural amber glass construction of the 4157NA produces an amber output directly from the glass rather than relying on a colored lens, which is a relevant fitment detail when replacing bulbs in housings designed for this configuration.
• The "NA" suffix in the 4157NA designation specifically denotes the natural amber glass variant, distinguishing it from the clear-glass 4157 bulb. Substituting a clear 4157 in a position specified for the 4157NA may affect the color output of the light assembly.