GM Service Manual Online
For 1990-2009 cars only

Notice: Horizontal aiming must be performed before making any adjustments to the vertical aim. Adjusting the vertical aim first will result in an incorrect headlamp aim.

To adjust the vertical aim, do the following:

  1. Follow the steps listed under Headlamp Horizontal Aiming first before adjusting the vertical aim if horizontal aiming needs to be performed.

  2. Object Number: 810592  Size: B2
  3. Find the aim dot on the lens of the low-beam lamps.
  4. Measure the distance from the ground to the aim dot on each lamp; if left low beam, subtract 2 inches (5 cm). Record this distance.

  5. Object Number: 822593  Size: B3
  6. At the wall or other flat surface, measure from the ground upward the recorded distance from Step 3 and draw or tape a horizontal line the width of the vehicle.
  7. Turn on the low-beam headlamps.
  8. Notice: Do not cover a headlamp to improve beam cut-off when aiming. Covering a headlamp may cause excessive heat build-up which may cause damage to the headlamp.

  9. Place a piece of cardboard or equivalent in front of the headlamp not being aimed. This should allow only the beam of light from the headlamp being aimed to be seen on the flat surface.

  10. Object Number: 810595  Size: A2

    Turn the vertical aiming screw (C) until the headlamp beam is aimed to the horizontal tape line.

  11. The top edge of the cut-off should be positioned at the bottom edge of the horizontal tape line.
  12. Repeat the steps for the opposite headlamp.