The Kenworth T450 front turn signal requires a 1157 bulb size, while rear turn signals accommodate either 1156 or 1157 bulb sizes. The replacement chart covers 1993 through 1997 production years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Kenworth T450 front turn signal position uses the 1157 bulb across all listed model years from 1993-1997.
The 1157 is a dual-filament bulb operating at 12V with a 21W/5W output rating and a BAY15d bayonet base, conforming to ANSI standards recognized in the US and Canada.
The dual-filament design of the 1157 allows it to serve two lighting functions within a single housing, with the higher 21W filament handling the active signal and the lower 5W filament serving a secondary role such as a running or parking light.
The rear turn signal position on the Kenworth T450 does not follow a uniform bulb specification across all listed years, with the 1157 fitted in 1993 and 1995, and the 1156 fitted in 1994, 1996, and 1997.
The 1156 is a single-filament bulb operating at 12V with a 21W output rating and a BA15s bayonet base, also conforming to ANSI standards recognized in the US and Canada.
Although the 1157 and 1156 share the same 21W primary filament wattage and a visually similar bayonet base profile, their bases are not interchangeable. The BAY15d base of the 1157 has two offset pins, while the BA15s base of the 1156 has a single pin, preventing cross-installation.
The rear turn signal position on the T450 requires year-specific verification before bulb selection, given that the 1993 and 1995 model years call for the 1157 while the surrounding years call for the 1156.