Peterbilt 587 Parking Light Bulb Size

The Peterbilt 587 parking light requires a 4157 bulb size for the specific lighting component located on the exterior of the vehicle. Data for the bulb specifications covers the range from 2011 to 2018.

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
2011-2018	4157

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament wedge bulb (T25). 12V, 27W/7W.	4157

Other Locations

Additional Notes

The Peterbilt 587 uses the 4157 bulb for its parking light across all listed model years, spanning 2011-2018.
The 4157 is classified under the ANSI standard, meaning it conforms to a standardized specification recognized in both the United States and Canada.
The 4157 is a dual-filament bulb, which means it contains two separate filaments within a single housing, each serving a distinct lighting function at different wattages.
The bulb operates on a 12-volt electrical system, consistent with standard automotive and commercial truck electrical architecture.
The two filaments in the 4157 are rated at 27 watts and 7 watts respectively, with the higher-wattage filament typically associated with the brighter stop or turn signal function and the lower-wattage filament associated with the parking or running light function.
The 4157 follows a T25 wedge form factor, referring to a wedge-base bulb with a tubular glass envelope roughly 25 millimeters wide, which seats directly into a compatible socket without a separate metal base.
Because the 4157 is a dual-filament type, single-filament substitutes would not replicate the full electrical behavior of the original bulb and would be incompatible with the socket's wiring configuration.