How to adjust headlights

@manueladronen here is the 1999 2006 Silverado Chassis Electrical System Chapter Opti and page 14 deals with the headlight adjustments. Great description about the actual adjustment for the DIY'er is: Point the truck at a wall on a level surface at 20' away from the front of the headlight to the wall. At night with the low beams on. With at least a 1/2 a tank of gas. On your headlight is a small dimple that is used for measuring the height of the center of the low beam. Find it, measure it to the ground. Now go to the wall the headlights are projecting on. Mark the measurement and if the low beam center line is any more than 1 1/2" to 2" above that mark turn the hex head above your headlight CLOCKWISE to lower them until the beam is nearly 2" lower (from here)