Peterbilt 520 Tail Light Bulb Size

The Peterbilt 520 tail light utilizes a 1157 bulb size for the specific lighting component located at the rear of the vehicle. Data for the bulb specifications covers the range from 2017 to 2019.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2017-2019	1157

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157

Other Locations

Additional Notes

The 1157 is the tail light bulb size for the Peterbilt 520 across the 2017-2019 model years.
The 1157 is an ANSI-standardized bulb type, meaning its physical and electrical characteristics conform to a defined North American specification recognized in both the United States and Canada.
The 1157 uses a dual-filament design, which allows a single bulb to serve two lighting functions, typically a lower-intensity running light and a higher-intensity brake or stop light signal.
The bulb operates on a 12-volt electrical system, consistent with the standard automotive and commercial vehicle electrical architecture found in most North American trucks.
The two filaments in the 1157 are rated at 21 watts and 5 watts respectively, with the higher-wattage filament corresponding to the brighter stop or turn signal function.
The 1157 uses a BAY15d bayonet base, a two-pin offset base type that physically prevents incorrect single-filament bulbs from being seated in the socket, as the offset pin spacing is specific to dual-filament applications.