This lamp provides illumination for the license plate on the rear of the host tractor. It is a sealed assembly that houses the bulb and connects to the vehicle's electrical system. The lamp is mounted using two fasteners through its housing, and the electrical connection is made via the threaded studs. A failed lamp results in a non-illuminated license plate, which can lead to a road-safety violation. On replacement, ensure the electrical connections are clean and the mounting fasteners are tightened to secure the housing against vibration.