The Peterbilt 387 front and rear turn signal bulbs both utilize a 2057 size bulb for proper operation. The replacement chart covers vehicle production spanning 2000 to 2009.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Peterbilt 387 uses the 2057 bulb for both its front and rear turn signals across the 2000-2009 model years.
The 2057 is an ANSI-standardized bulb type recognized in both the United States and Canada.
It is a dual-filament bulb, meaning it contains two separate filaments that operate at different wattages within a single housing.
The 2057 operates on a 12-volt electrical system and draws 26.9 watts on its high-intensity filament and 8 watts on its low-intensity filament.
The bulb uses a BAY15d bayonet base, a two-pin base type where the two pins are offset at different heights to ensure correct orientation during installation.
The 2057 is a brighter variant of the 1157 bulb, sharing the same BAY15d base type, which means the two types are physically interchangeable in many applications.
Because the 1157 and 2057 share the same base, an 1157 may fit the socket of the Peterbilt 387, though the 2057 produces greater output on its primary filament.