Kenworth L700 front turn signal bulbs use 1157 size while rear turn signal bulbs accommodate 1156 or 1157 size specifications. The replacement chart covers vehicle production spanning 1981 to 1987.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Kenworth L700 front turn signal position uses the 1157 bulb across all model years covered in the specifications, from 1981-1987.
The 1157 is a dual-filament bulb rated at 12V with a 21W/5W output, meaning it carries one filament for the higher-intensity turn signal function and a second filament for a lower-intensity running light function.
The 1157 bulb uses a BAY15d bayonet base, a two-pin offset base that physically prevents substitution with single-filament bayonet bulbs sharing a similar form factor.
The rear turn signal position on the Kenworth L700 does not use a single bulb type across all listed years, with the 1157 specified for 1981-1983 and the 1156 specified for 1984-1985 and 1987.
The 1986 rear turn signal retains the 1157, which differs from the adjacent 1985 and 1987 model years, both of which specify the 1156 for that position.
The 1156 is a single-filament bulb rated at 12V and 21W, using a BA15s bayonet base with a single locating pin, making it incompatible as a direct replacement for the dual-filament 1157 despite sharing a similar voltage and wattage rating on the primary filament.
Both the 1157 and 1156 conform to ANSI standards recognized in the United States and Canada, placing them within the same standardized bulb classification system.
The base type difference between the 1157 (BAY15d) and the 1156 (BA15s) is a critical fitment distinction for the Kenworth L700 rear turn signal, as the two bulbs are not interchangeable despite their similar physical appearance.