Vehicle Preparation

Prepare the vehicle for adjusting the headlamp beam aim:

Fig 1: Vehicle & Aiming Area
Courtesy of GENERAL MOTORS CORP.
1. Verify that all the components are in place on the vehicle, if other service has been performed on the vehicle.
2. The vehicle must have a full tank of gas.
3. Verify that the tires are inflated to the proper pressures.
4. Stop all other work on the vehicle.
5. Position the vehicle squarely with the aiming screen and with the headlamp directly over the reference line which is painted or taped on the floor.
6. Locate the vertical center line on the aiming screen (3) to be in line with the center of the vehicle (4). This can be accomplished by sighting through the center of the rear window and over the hood.

   Mark the vertical center of the front and rear windows with narrow tape. Use these marks as sights to locate the centerline of the vehicle. Move the vehicle or the screen until the center line of the screen comes into alignment with the 2 points.

7. Close the doors.
8. Rock the vehicle sideways to stabilize the suspension.
9. Measure the height (6) from the floor to the aiming dots of the headlamps. Adjust the horizontal tape (1) on the aiming screen to match this dimension.
10. Measure the distance (5) between the headlamp aiming dots. Position the vertical tapes (2) this distance equally to the right and left of the centerline.