2009 Hummer H3T Alpha Owner's Manual - Page 132

3-14 Instrument Panel There is a delay in the transition between the daytime and nighttime operation of the Daytime Running Lamps (DRL) and the automatic headlamp system so that driving under bridges or bright overhead street lights does not affect the system. The DRL and automatic headlamp system will only be affected when the light sensor detects a change in lighting lasting longer than the delay. If the vehicle is started in a dark garage, the automatic headlamp system will come on immediately. Once the vehicle leaves the garage, it will take about one minute for the automatic headlamp system to change to DRL if it is light outside. During that delay, the instrument panel cluster may not be as bright as usual. Make sure the instrument panel brightness control is in the full bright position. See Instrument Panel Brightness on page 3-15. Automatic Headlamp System When it is dark enough outside, the automatic headlamp system will turn on after the transmission has been shifted from P (Park) to D (Drive). The headlamps, taillamps, sidemarker, parking lamps, roof marker lamps, and the instrument panel lights turn on at normal brightness. The radio lights will become dimmer when the headlights are off compared to when the headlights are on. The vehicle has a light sensor located on the top of the instrument panel. Do not cover the sensor, or the system will be on whenever the ignition is on. The system can turn on the headlamps when driving in a parking garage, through a tunnel or when there is overcast weather. This is normal. Off-Road Lamps The off-road lamps, if the vehicle has them, provide auxiliary lighting when the vehicle is used off road. These lamps are not intended to be used in place of existing vehicle lighting. The lamps are not to be used on any public street or highway and are to be covered when not in use. Check your state and local laws before installing or using any auxiliary lighting. In some states it may be necessary to remove the roof lamps when operating the vehicle on the highway.