2011 Chevrolet Silverado 1500 Regular Cab Owner's Manual - Page 212

6-4 Lighting When it begins to get dark, the automatic headlamp system switches from DRL to the headlamps. To turn off the DRL lamps, turn the exterior lamps control to the OFF position and then release. For vehicles first sold in Canada, the transmission must be in the P (Park) position before the DRL lamps can be turned off. Automatic Headlamp System When it is dark enough outside, the automatic headlamp system turns on the headlamps at the normal brightness, along with the taillamps, sidemarker, parking lamps, and the instrument panel lights. The radio lights will also be dim. To turn off the automatic headlamp system, turn the exterior lamps switch to the off position and then release it. For vehicles first sold in Canada, the transmission must be in the P (Park) position before the automatic headlamp system can be turned off. The vehicle has a light sensor located on the top of the instrument panel which regulates when the automatic headlamps turn on. Do not cover the sensor, otherwise the headlamps will come on whenever the ignition is on. The system may also turn on the headlamps when driving through a parking garage or heavy overcast weather. This is normal. There is a delay in the transition between the daytime and nighttime operation of the Daytime Running Lamps (DRL) and the automatic headlamp systems so that driving