2012 GMC Sierra Owner's Manual - Page 425

Vehicle Care 8. Turn the vertical aiming screw until the headlamp beam is aimed to the horizontal tape line. Turn it clockwise or counterclockwise to raise or lower the angle of the beam. 10-39 Bulb Replacement For the proper type of replacement bulbs, see Replacement Bulbs on page 10‑43. For any bulb‐changing procedure not listed in this section, contact your dealer. Headlamps, Front Turn Signal, Sidemarker, and Parking Lamps Halogen Bulbs { WARNING 9. Make sure that the light from the headlamp is positioned at the bottom edge of the horizontal tape line. The lamp on the left (A) shows the correct headlamp aim. The lamp on the right (B) shows the incorrect headlamp aim. 10. Repeat Steps 7 through 9 for the opposite headlamp. Halogen bulbs have pressurized gas inside and can burst if you drop or scratch the bulb. You or others could be injured. Be sure to read and follow the instructions on the bulb package. A. Side Marker Lamp B. Low-Beam Headlamp C. High-Beam Headlamp D. Park/Turn Signal Lamp 1. Open the hood. See Hood on page 10‑5 2. When replacing a driver side bulb on a vehicle with duel batteries, see your dealer.