The Peterbilt 349 front and rear turn signal bulbs utilize a 2057 or 198 size. The replacement chart covers 1986 to 1987 production years 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 2057 bulb is the most frequently specified size across the Peterbilt 349 turn signal applications in these specifications, appearing in both front and rear positions across the 1986-1987 model years.
The 2057 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a wattage split of 26.9W and 8W, representing its high and low filament outputs respectively. It is classified as a brighter variant of the 1157 under the ANSI standard recognized in the US and Canada.
The 198 is a miniature wedge bulb of the T5 type, rated at 12V and 2W. Its single-filament, low-wattage design contrasts sharply with the dual-filament 2057, meaning the two bulb types are not interchangeable despite appearing in the same vehicle positions across different configurations.
For the 1987 Peterbilt 349 front turn signal, the required bulb size depends on headlamp configuration. Vehicles with 4 round headlamps take the 198, while the standard application calls for the 2057.
The rear turn signal on the 1986 Peterbilt 349 follows a similar configuration split. The 2057 is specified for vehicles with 4 rectangular headlamps, while the 198 applies to the alternate configuration.
The BAY15d base of the 2057 features two offset pins that lock the bulb into its socket at a fixed rotational position, which is a functional requirement given its dual-filament design. This base type is physically incompatible with the wedge-style socket used by the 198.