Freightliner Cascadia Parking Light Bulb Size

Additional Notes

• The Freightliner Cascadia uses the 4157NA bulb for its parking light across all listed model years from 2008-2017, making it the sole bulb type specified for this application.
• The 4157NA is a dual-filament bulb, operating at 27 watts on its primary filament and 7 watts on its secondary filament, which allows it to serve both higher-intensity and lower-intensity lighting functions within a single unit.
• The bulb operates on a 12-volt electrical system, consistent with standard automotive and commercial vehicle electrical architecture.
• The 4157NA carries ANSI standardization recognized in both the United States and Canada, meaning it conforms to a defined set of performance and dimensional criteria shared across compliant manufacturers.
• The "NA" designation in 4157NA refers to the natural amber glass envelope, which produces an amber-tinted output without the use of a separate colored lens or filter.
• The T25 designation identifies the bulb's wedge-type form factor, where the base of the bulb itself acts as the connector rather than a separate metal base, a design that reduces the risk of corrosion at the contact point.
• The 4157 and 4157NA share the same physical form factor and filament configuration, but substituting a clear 4157 for the 4157NA would alter the output color, which may affect compliance with lighting regulations that specify amber for parking light positions.