The Volvo VNL front turn signal requires a 3157NA bulb size while rear turn signal applications use either 3157 or 1157 bulb sizes. The replacement chart covers vehicle production spanning 2005 to 2017 with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 3157NA is the most frequently specified bulb across the Volvo VNL turn signal positions covered in these specifications. It appears in the front turn signal position for every model year from 2005 through 2017, as well as in the rear turn signal position for 2014 and 2015.
The 3157NA is a dual-filament T25 wedge bulb rated at 12V with a high filament of 27W and a low filament of 7W. Its defining characteristic relative to the standard 3157 is its natural amber glass envelope, which produces an amber-colored output without relying on a colored lens.
The standard 3157 shares the same T25 wedge base, 12V operating voltage, and 27W/7W dual-filament configuration as the 3157NA. The sole distinction between the two is the absence of the natural amber glass coating on the 3157.
Because the 3157 and 3157NA share the same base type and electrical ratings, they are physically interchangeable. However, substituting a clear 3157 for a 3157NA in a housing designed without an amber lens would alter the output color of the turn signal.
The 1157 uses a BAY15d bayonet base rather than a wedge base, making it physically incompatible with sockets designed for the T25 wedge format used by the 3157 and 3157NA. The two bulb families cannot be substituted for one another.
The 1157 is rated at 12V with a high filament of 21W and a low filament of 5W, which represents a lower wattage output on both filaments compared to the 27W/7W rating of the 3157 series.
In the Volvo VNL rear turn signal position, the 1157 was specified for model years 2005-2012, while the 3157 replaced it for 2014-2015. These two bulb types are not interchangeable due to their differing base designs.
For the 2016-2017 Volvo VNL front turn signal, the 3157NA specification carries a conditional note indicating it applies specifically to vehicles equipped with halogen capsule headlamps, distinguishing those configurations from others that may exist in those model years.
All three bulb types covered in these specifications conform to ANSI standards applicable in the United States and Canada, indicating standardized dimensional and electrical tolerances across manufacturers producing these part numbers.
The dual-filament design of all three bulb types allows a single bulb to serve both a higher-intensity function and a lower-intensity function within the same socket, a configuration commonly used when a turn signal position also serves as a running or parking light.