Kenworth C540 front and rear side marker bulbs utilize 904, 1157, and 67 bulb sizes depending on location and model variation. The replacement chart covers 1985 through 1993 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 Kenworth C540 side marker bulb specifications cover three distinct bulb types across the front and rear positions: the 904, 1157, and 67.
The 904 is a T10 miniature wedge bulb rated at 12V and 8W, conforming to ANSI standards for the US and Canadian markets. Its wedge base design means it requires no locking mechanism, as the bulb is held in place by tension within the socket.
The 1157 is a dual-filament bulb with a BAY15d bayonet base, rated at 12V with a 21W/5W filament configuration. The dual-filament design allows it to serve two lighting functions within a single housing, such as running light and turn signal operation simultaneously.
The 67 is a single-filament bulb with a BA15s bayonet base, rated at 12V and 8W. It is described as a lower wattage variant of the 1156 bulb, sharing the same base type but drawing less power.
All three bulb types conform to ANSI standards applicable in both the United States and Canada.
The front side marker position on the Kenworth C540 uses the 904 for the 1993 model year, while the 1992 and 1985 model years use the 1157. These two bulb types are not interchangeable, as they differ in base type, filament count, and wattage.
The rear side marker position uses the 67 for the 1993 model year, while the 1992 and 1985 model years use the 904. The 67 and 904 share the same 8W rating but differ in base type, making them physically incompatible without socket modification.
The 1157 and 67 both use bayonet-style bases, but the 1157 uses a BAY15d base with offset pins to prevent incorrect installation, while the 67 uses a BA15s base with a single contact. These two bases are not interchangeable despite their similar locking mechanism.