The exterior lamp control is on the instrument panel to the left of the steering wheel. O (Off) : Turns off the automatic headlamps and Daytime Running Lamps (DRL). Turn the headlamp control to the off position again to turn the automatic
headlamps or DRL back on. For vehicles first sold in Canada, off will only work when the vehicle is in P (Park).
My Silverado originated in Canada and I'm inquiring how automatic headlights & DRL can be changed to turn off when vehicle is in Drive or Reverse. Currently if transmission is in gear headlights or DRL will override any selection on the
exterior lamp control.