Kenworth T800 front and rear side marker bulbs utilize 1157, 67, and 904 bulb sizes depending on location and model variation. The replacement chart covers vehicle production spanning 1987 to 1997 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 1157 bulb is the most frequently specified front side marker bulb for the Kenworth T800, covering model years 1987 and 1990-1997. It is a dual-filament bulb rated at 12V with a 21W main filament and a 5W secondary filament, mounted on a BAY15d bayonet base.
The 904 bulb is the dominant rear side marker bulb for the Kenworth T800, specified across model years 1987-1990 and 1993-1997. It is a miniature wedge-style T10 bulb rated at 12V and 8W.
The 67 bulb appears in both front and rear side marker positions across select years. It is a single-filament bulb rated at 12V and 8W, using a BA15s bayonet base, and is considered a lower-wattage variant of the 1156 bulb type.
The front side marker position on the Kenworth T800 uses three distinct bulb types across the 1987-1997 model range: the 1157, the 67, and the 904, indicating that the position is not served by a single universal fitment across all years.
The 1157 and 67 bulbs both use bayonet-style bases, but they are not interchangeable. The 1157 uses a BAY15d dual-contact base, while the 67 uses a BA15s single-contact base. These two base types are physically and electrically incompatible.
The 904 wedge-style bulb and the 1157 bayonet bulb are also not interchangeable, as they use fundamentally different mounting and contact systems despite both being 12V bulbs.
For the 1989 Kenworth T800 front side marker, the specified bulb is the 67, while the rear side marker for the same year uses the 904. The two positions require different bulbs in that model year.
For the 1991-1992 Kenworth T800, the rear side marker uses the 67 bulb, whereas surrounding model years in that position specify the 904. These two years represent an exception within the broader rear side marker fitment pattern.
All three bulb types referenced in these specifications, the 1157, 67, and 904, conform to ANSI standards applicable in both the United States and Canada.
The 1157 is the only dual-filament bulb among the three types specified. Its higher primary wattage of 21W distinguishes it from the 8W single-filament ratings of both the 67 and the 904.