Kenworth C500 front and rear side marker bulbs utilize 904, 67, or 1157 bulb sizes depending on production specifications. The replacement chart covers 1981 through 1997 model years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Kenworth C500 front and rear side marker positions draw from three distinct bulb types across the 1981-1997 model range: the 904, the 67, and the 1157.
The 904 is a T10 miniature wedge bulb rated at 12V and 8W under the ANSI standard applicable in both the US and Canada. Its wedge base design requires no locking mechanism, as the socket itself retains the bulb through friction.
The 67 is a single-filament bulb with a BA15s bayonet base, also rated at 12V and 8W. The BA15s base uses a single locating pin, which means it is not interchangeable with dual-pin bayonet sockets without modification.
The 1157 is a dual-filament bulb with a BAY15d bayonet base rated at 12V and 21W/5W. The BAY15d base uses two offset pins to prevent incorrect installation, and its dual-filament design serves two independent brightness levels within a single housing.
Although the 904 and the 67 share the same 12V, 8W electrical rating, their base types are entirely different. The 904 uses a wedge base while the 67 uses a BA15s bayonet base, making the two bulbs physically non-interchangeable despite identical wattage.
The 1157 draws significantly more current on its primary filament at 21W compared to the 8W rating of both the 904 and the 67. Substituting an 8W bulb in a socket designed for the 1157 would result in reduced output and potential non-compliance with lighting standards.
For the front side marker on the Kenworth C500, the 1157 appears in 1981, 1985, 1988, and 1990, while the remaining years use either the 904 or the 67, indicating that the front position has seen the widest variation in bulb type across the covered range.
The rear side marker position shows a strong prevalence of the 904 bulb, which is specified for the majority of years from 1984 through 1997, with isolated exceptions in 1981, 1982, 1983, and 1993.
In 1993, the front and rear side marker positions use opposite bulb types: the front specifies the 904 while the rear specifies the 67. Both share the same wattage but require different sockets, so the two positions are not served by a single interchangeable bulb that year.
In 1997, both the front and rear side marker positions on the C500 specify the 904 bulb, making it the only year in the covered range where a single bulb type serves both side marker positions simultaneously.