Peterbilt 587 front turn signal bulbs use 4157 size while rear turn signal bulbs use 1157 size. The replacement chart covers 2011 through 2018 production years with bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Peterbilt 587 uses the 4157 bulb for the front turn signal across all model years from 2011 to 2018.
The 4157 is a dual-filament T25 wedge bulb rated at 12V with a 27W high filament and a 7W low filament, conforming to ANSI standards recognized in both the United States and Canada.
The rear turn signal on the Peterbilt 587 uses the 1157 bulb across all model years from 2011 to 2018.
The 1157 is a dual-filament bulb rated at 12V with a 21W high filament and a 5W low filament, fitted with a BAY15d bayonet base, and also conforms to ANSI standards recognized in both the United States and Canada.
The front and rear turn signal positions on the Peterbilt 587 use different bulb types, meaning the 4157 and 1157 are not interchangeable between those positions despite both being dual-filament 12V ANSI-standard bulbs.
The 4157 uses a wedge-style base while the 1157 uses a BAY15d bayonet base, which represents a fundamental physical difference that prevents cross-position substitution.
Both bulbs carry dual-filament designs, which is typical for turn signal applications that also serve a secondary lighting function such as parking or running lights.