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Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4087
Experience:  Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
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2007 trailblazer: adjust..the drivers side headlight is aimed way

Resolved Question:

how do i adjust the headlights on my 2007 trailblazer, the drivers side headlight is aimed way to high and i got pulled over for it.
Submitted: 9 years ago.
Category: Chevy
Expert:  Bob replied 9 years ago.

Hello, The dealers have a special set of tools that they use to aim the lamps mechanically. But those are really expensive and the alternative method is listed below for you. It is a little work, but the end result should be worth the effort. Thanks,Bob


Document ID# XXXXX
2007 Chevrolet TrailBlazer - 4WD

Headlamp Aiming

Screen Method for Headlamp Aiming

The screen method requires an area set up specifically for headlamp aiming.

Object Number: 418400  Size: SH

The area should consist of a level surface large enough to allow for a vehicle and an additional 7.62 m (25 ft) as measured from the face of the headlamps to the aiming screen.

Object Number: 771622  Size: SH

The screen should be a wall or other flat surface at least 1.52 m (5 ft) high by 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and 90 degrees to the floor. The screen should be provided with a permanent vertical reference line 0.61 m (2 ft) from the left edge of the screen, 2 laterally adjustable vertical tapes, and one vertically adjustable horizontal tape.

After the aiming screen has been set up and located, paint or tape a reference line on the floor 15.24 m (50 ft) from the vertical reference line on the screen. This line should be perpendicular to the aiming screen and a mark placed at 7.62 m (25 ft) from the screen.

Headlamp Aiming Procedure
  1. Align the left tires of the vehicle with the reference line extending from the screen with the headlamps aligned with the reference line.
  2. Remove any snow, ice or mud from the vehicle.
  3. The vehicle must be fully assembled and all other work stopped while the headlamp aiming is being done.
  4. The vehicle must contain one person or approximately 160 lb (73 kg).
  5. Tires should be properly inflated.
  6. Rock the vehicle to stabilize the suspension.
    Object Number: 791936  Size: SH

  7. Measure from the floor to the reference mark on the headlamp lens (2). The graphic shows a GMC headlamp. Chevrolet and Oldsmobile are similar.
  8. At the screen, measure from the floor and place the horizontal tape at the above measured distance.
  9. Turn the low beam headlamps ON.
  10. The graphic shows the vertical (1) adjustment, no horizontal adjustments are required. The graphic shows a GMC headlamp. Chevrolet and Oldsmobile are similar. Adjust the headlamps to the specifications required by state and local authorities.
    Object Number: 792177  Size: SH

  11. The beam pattern must be positioned as shown in the graphic.

    Important: Do not place a cover directly on the headlamp assembly while the headlamp is ON.

  12. Adjust one headlamp at a time while blocking the light from the other. The cover must be away from the headlamp. The following list refers to the callouts in the graphic:
    - The low beam centerline reference mark (4).
    - Distance from ground to the low beam bulb centerline reference mark (1).
    - The ground line (2).
    - Horizontal edge of the low beam headlamp pattern (3).
    - The edge of the headlamp pattern (3), must be 5 cm (2 in) below the reference mark (4), with the vehicle 7.62 m (25 ft) away.

Document ID# XXXXX
2007 Chevrolet TrailBlazer - 4WD
Customer: replied 9 years ago.
Bob, the message says there is no horizontal adjustment, but my drivers side headlight is aimed much higher than the passenger one, i have the vehichle parked so that I may adjust the light, but what if turning the adjustment knob has no effect. Do I turn it clockwise or counterclockwise? and what happens if it does not adjust? thanks for your help.
Expert:  Bob replied 9 years ago.
I think that the vertical adjustment will also move the horizontal some, but I don't know for sure or how much if it does. If turning the adjuster has no effect, you may want to look and see if it is stripped or broken or something. I would really think that since the truck is an 07, the dealer should fix it under warranty. I can't imagine any way it could be out of adjustment unless it was shipped that way, or unless it has suffered some kind of impact damage.
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