Freightliner Columbia Parking Light Bulb Size

Additional Notes

• The Freightliner Columbia uses the 4157NA bulb for its parking light across all listed model years from 2000-2017, representing an uninterrupted fitment of a single bulb type throughout that entire span.
• The 4157NA is a dual-filament bulb, meaning it serves two lighting functions within a single housing, operating at 27 watts on the higher filament and 7 watts on the lower filament.
• The bulb operates on a 12-volt electrical system, which is standard for automotive and commercial vehicle lighting circuits.
• The 4157NA carries an ANSI designation, indicating it conforms to a standardized specification recognized in both the United States and Canada.
• The natural amber glass of the 4157NA produces a yellow-tinted output directly from the glass envelope itself, rather than relying on an amber-colored lens in the vehicle's housing to achieve the color.
• The T25 designation refers to the bulb's tubular glass envelope, with the number indicating its width in eighths of an inch, placing it in a well-established size category used across many vehicle applications.
• Because the 4157NA uses a wedge base rather than a bayonet or screw base, it is retained by friction fit within its socket, and substituting a bulb with a different base type would result in an incompatible fitment.
• The standard non-amber variant of this bulb family is the 4157, and while the base and filament configuration are shared, substituting the 4157 for the 4157NA would produce white rather than amber output, which may not meet regulatory requirements for parking light color.