Peterbilt 567 Parking Light Bulb Size

Additional Notes

• The Peterbilt 567 parking light bulb specifications cover model years 2014-2020 and reference three distinct bulb types: 3157, 4157, and 4157NA.
• All three bulb types share the same electrical and physical foundation, operating at 12 volts with a dual-filament output rated at 27W for the high filament and 7W for the low filament.
• Each bulb follows the T25 wedge form factor and conforms to ANSI standards recognized in both the United States and Canada.
• The dual-filament design allows a single bulb to serve two lighting functions simultaneously, which is typical in parking light assemblies that also handle turn signal or running light duties.
• The 4157NA variant is distinguished by its natural amber glass envelope, which produces an amber-colored output without the use of a separate amber lens or filter.
• The 4157 and 3157 types produce output through a clear glass envelope, meaning any amber coloring in those applications is achieved through the vehicle's lens rather than the bulb itself.
• The Peterbilt 567 (2018-2020) uses the 3157 bulb, while 2014 and 2016-2017 model years use the 4157NA, and the 2015 model year uses the 4157.
• Although the 3157, 4157, and 4157NA share identical voltage and wattage ratings, the glass envelope differences between them represent a fitment distinction that affects the color output of the parking light assembly.