2008 GMC Sierra 1500 Pickup Owner's Manual - Page 361

Headlamp Aiming The vehicle has a visual optical headlamp aiming system. The aim of the headlamps have been preset at the factory and should need no further adjustment. However, if the vehicle is damaged in a crash, the aim of the headlamps may be affected and adjustment may be necessary. If oncoming vehicles flash their high beams at you, this may mean the vertical aim of your headlamps needs to be adjusted. It is recommended that the vehicle is taken to your dealer/retailer for service if the headlamps need to be adjusted. It is possible however, to re-aim the headlamps as described. The vehicle should: • Be placed so the headlamps are 25 ft. (7.6 m) from a light colored wall. • Have all four tires on a level surface which is level all the way to the wall. • Be placed so it is perpendicular to the wall. • Not have any snow, ice, or mud on it. • Be fully assembled and all other work stopped while headlamp aiming is being performed. • Normally loaded with a full tank of fuel and one person or 160 lbs (75 kg) sitting on the driver seat. • Have the tires properly inflated. • Have the spare tire is in its proper location in the vehicle. Headlamp aiming is done with the vehicle's low-beam headlamps. The high-beam headlamps will be correctly aimed if the low-beam headlamps are aimed properly. 5-49