2010 GMC Savana 2500 Cargo Owner's Manual - Page 158

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 under bridges or bright overhead street lights does not affect the system. The DRL and automatic headlamp system is only affected when the light sensor sees a change in lighting lasting longer than the delay. If the vehicle is started in a dark garage, the automatic headlamp system comes on immediately. Once the vehicle leaves the garage, it takes approximately 30 seconds 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 4-12. Dome Lamps The dome lamps come on when any door is opened. They turn off after all the doors are closed. Instrument Panel Brightness The knob for this feature is located next to the exterior lamps control. The dome lamps can also be turned on by turning the instrument panel brightness knob, located on the instrument panel to the left of the steering column, clockwise to the farthest position. In this position, the dome lamps remain on whether a door is opened or closed. D (Instrument Panel Lights): Push the knob to extend and then turn clockwise or counterclockwise to brighten or dim the instrument panel lights and the radio display. This only works if the headlamps or parking lamps are on. To turn on the dome lamps, with the vehicle doors closed, turn the knob all the way clockwise. 4-12