On certain trucks, the tail lamps do not turn on when the daytime running lamps (DRLs) are on. Canadian regulations require that, if a vehicle has dash backlighting, the low beam headlamps and tail lamps must automatically switch on when it is dark or the tail lamps must stay on at all times.
Safety Risk
Driving without tail lamps in low light conditions could make the truck less visible and increase the risk of a crash.
Corrective Actions
Daimler Truck North America (DTNA) will notify owners by mail and instruct you to take your truck to a DTNA authorized service facility to update the parameters for the lighting system. For Western Star 4700 ZODIAC models, the service facility will replace or modify the wiring harness.