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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Grand Prix 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Headlamp Aiming

Headlamp Aiming Visual Method

Visual Aiming Procedure

Important: Some state and local laws specify requirements for headlamp aim. All of these laws must be complied with when performing any headlamp aiming operations.

Headlamp aim should be checked:

    • When a new headlamp capsule is installed
    • If service or repairs to the front end area have (or may have) disturbed the headlamps or their mounting
   • 
  • The area will consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 ft) measured from face of lamps to the front of the aiming screen.
    •    • 
  • The screen will be 1.52 m (5 ft) high x 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and properly adjusted to the floor on which the vehicle stands. Provisions may be made for moving the screen so it can be aligned parallel with the vehicle.
    •    • 
  • The screen shall be provided with a fixed vertical centerline, two laterally adjustable vertical tapes, and one vertically adjustable horizontal tape.
    •    • 
  • If a regular commercial aiming screen is not available, the screen may consist of a vertical wall having a clear uninterrupted area approximately 1.83 m (6 ft) high and 3.66 m (12 ft) wide. The surface should be finished with a washable non-gloss white paint.
    •    • 
    Object Number: 280087 Size: SH
  • After the aiming screen has been set up in its permanent location, it is necessary to paint a reference line on the floor directly under the lens of the lamps to indicate the proper location of the headlamps when they are being aimed:
    •    - Distance between headlamps (1)
       - Center line of screen (2)
       -  Adjustable vertical pointer (3)
       -  Adjustable horizontal tape (4)
       - Diagram of light screen (5)
       - Vertical center line ahead of right headlamp pointer position (6)
       - 7.62 m (25 ft) (7)
       - Car axis (8)
       - Adjustable vertical pointer
       - Horizontal center line of lamps
       - Vertical center line ahead of left headlamp

    Prior to aiming the headlamps, the following steps must be taken:

    1. Remove any snow, ice or mud from the vehicle.
    2. The vehicle must have a full tank of gas.
    3. Stop all other work on the vehicle.
    4. If any service has been performed on the vehicle, make sure that all of the components are back in their original place.
    5. The vehicle must be on a level surface.

      6. Object Number: 418380 Size: SH
    6. The vehicle left tires must be aligned with the reference line extending from the screen with the headlamps aligned with the reference line.
    7. Do not load any cargo in the vehicle.
    8. The vehicle must contain one person or 72.56 kg (160 lb) on the driver's seat.
    9. Inflate the tires to the proper pressure.
    10. Simulate the vehicle loads if the intended use of the vehicle is for hauling heavy loads or towing a trailer.
    11. Rock the vehicle in order to stabilize the suspension.
    12. Turn on the headlamps to low beam and observe the left and the top edges of the high intensity zone on the screen. The edges of the high intensity zone should fall within the specifications.

    Headlamp Aiming Procedure
    1. Open the hood.

      2. Object Number: 418400 Size: SH
    2. Measure from the floor to the center of the headlamp bulb. (Some headlamps have an aim dot marked on the headlamp lens).
    3. At the screen, measure from the floor and place the horizontal tape at the measured distance.
    4. Measure from the reference line on the floor to the left headlamp bulb centerline.
    5. At the screen, measure from the reference line and place the vertical tape at the measured distance.
    6. Measure from the reference line on the floor to the right headlamp bulb centerline.
    7. At the screen, measure from the reference line and place the vertical tape at the measured distance.

      8. Important: DO NOT cover the headlamp, this may cause excessive heat build up.


      Object Number: 476831 Size: SH
    8. Turn on the low beam headlamps and block the light from projecting onto the screen from the passenger side headlamp.

      9. Object Number: 313009 Size: SH
    9. Adjust the horizontal aim screw  (2) and vertical aim screw  (1) of the headlamps to the specifications required by the state and the local authorities, or as shown in step number 8.
    10. Repeat the aiming procedure for the passenger side headlamp while blocking the light from projecting onto the screen from the driver side headlamp.
    11. Turn the headlamps OFF.
    12. Close the hood.

    Headlamp Aiming Mechanical Method

    Tools Required

    J 25300-D Headlamp Aimer


    Object Number: 313009 Size: SH

    If a headlamp testing machine is used, it should give results equivalent to those obtained using the screen method. It should be in good repair and adjustment, and should be used in accordance with the manufacturer's instructions. The machine using a photoelectric cell or cells to determine aim should also have a visual screen upon which the beam pattern is projected proportional to its appearance and aim on a screen at 7.62 m (25 ft). Such a visual screen should be plainly visible to the operator and should have horizontal and vertical reference lines to permit visual appraisal of the lamp beam.

    Horizontal and vertical aiming of each of the composite headlamps is done by turning adjusting screws which move the headlamp capsule in relation to the headlamp frame. The horizontal adjustment screw (2) is located on the rear middle edge of each of the headlamp assemblies, toward the center of the vehicle. The vertical adjustment screw (1) is located on the rear upper edge of each of the headlamp assemblies, toward the outboard side of the vehicle.

    Vehicle Preparation

    Prepare the vehicle for checking the headlamp beam aim as follows:

        • Make sure that all the components are in place on the vehicle, if other service has been performed on the vehicle.
        • Make sure the fuel level is 1/2 full or less.
        • Be sure tires are inflated to the proper pressures.
        • Stop all other operations of work on the vehicle.
        • Close the doors.
        • Rock the vehicle sideways to stabilize the suspension.

    Adjustment Procedure

      Object Number: 280078 Size: MH
    1. Raise the hood.

      2. Important: Select aim-adjusting tools carefully since one full turn of an adjusting screw will move the aim approximately 89 mm (3.5 in) when measured at 7.62 m (25 ft).

    2. Install the J 25300-D to the headlamp capsule lens.
    3. Calibrate the mechanical aimers (conforming to SAE J1602) as follows:
      4. 3.1. Set the master fixture to 0 up/down and 0 right/left.
      3.2. Calibrate the aimers on the master fixture to read 0 up/down and 0 right/left.
    4. Inspect the horizontal and vertical aim and adjust as necessary.
    5. Lower the hood.