Kenworth K220 Back Up Light Bulb Size

The Kenworth K220 back up light uses 1156 and P21W bulb sizes for the rear illumination system. Data for the specific lighting components covers the period from 1988 through 1994.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1994	1156
1988-1992	1156

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156

Other Locations

Additional Notes

The Kenworth K220 uses the 1156 bulb across all specified model years for the back up light position.
The years covered by these specifications span 1988-1992 and 1994.
The 1156 is an ANSI-standardized bulb type, meaning its physical and electrical characteristics are defined by a recognized North American standard used in both the United States and Canada.
The 1156 operates on a 12-volt electrical system and draws 21 watts, which is typical of incandescent automotive bulbs used in signaling and reversing light applications.
The 1156 is a single-filament bulb, meaning it serves one lighting function only, which is consistent with its use in a dedicated back up light circuit.
The BA15s designation refers to a bayonet-style base with a 15mm collar and a single locating pin, which determines physical fitment into the socket.
Because the BA15s base has only one pin, it is not interchangeable with the BA15d base, which carries two offset pins and is found on dual-filament bulbs such as the 1157.