Chevrolet Colorado & GMC Canyon Forum banner

1 - 9 of 9 Posts

65 Posts
Discussion Starter #1
The community here at urges you to please use caution and seek professional assistance when performing modifications to your vehicle. Before attempting any modification it is advised that you refer to your Colorado or Canyon service manual or contact a certified mechanic as not all GMT355 trucks are the same. The staff and the associated members are in no way responsible for any damages, injuries or other harm inflicted to your vehicle or yourself which may result in attempting these modifications. The posts and content presented on this site reflect in no way the views of or it’s ownership.

A 355nation How To presented by

Project Name
How To Adjust Your Headlights Vertically

Project Description
Change the vertical angle of your headlights to compensate for rake or bulb replacement.

Skill Level

Project Vehicle
Make: Chevrolet
Model: Colorado
Year: 2008
Engine: 2.9L
Power windows: No
Sun Roof: No

Tools Needed
(Year Dependent)
Torx T15
or 2.5 Allen Key

Project Time
15 minutes or less

Project Cost

Depending on the year of your truck, the set screw will either be a Torx or Philips style, but the work will be the same.

Step One: Ideally find level ground in front of a wall or garage door. If its dark it will be easier to adjust.

Step Two: Pop the hood.

Step Three: Locate set screw behind headlamp housing.

Step Four: Turn Clockwise to Lower, Counter-Clockwise to Raise the beam. I didn't have any Torx drivers around so I used a 2.5 Allen Key and it did the trick fine. It was daytime, but overcast when I did mine, and I'm OCD so I grabbed a tape measure to be real accurate.

Step Five: Admire your good work and drive safely.



Super Moderator
13,732 Posts
Re: How-To: Adjust Your Headlights Vertically

Headlamp Aiming

Screen Method for Headlamp Aiming

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

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.

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.
  7. Measure from the floor to the reference mark on the headlamp lens (2).
  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. Adjust the headlamps to the specifications required by state and local authorities.
  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.

US Army 19yrs and ......
45,284 Posts
Well done!

65 Posts
Discussion Starter #5
Hey, this was actually posted! haha

I had time on my hands and it seemed as though it would be useful to have documented, just trying to help out thats all.

Now I just need to find the time to get on here more often again.

1,235 Posts
Will this work if you have the dual light mod done and only on 1 side 1 beam is higher than other but other side they both the same
It should be the same, but if you have one bulb off-line it's probably not fully seated in the socket, or bad manufacturing/product. Check to see if it's 100% correct in the socket on your bad side.

65 Posts
Discussion Starter #8
Will this work if you have the dual light mod done and only on 1 side 1 beam is higher than other but other side they both the same
The set screw is only for the low beam. If that's the one thats out of whack a bit, then you're in luck to get everything pointing the same. If not, then I say take Iceman's advice and check to make sure it seated properly first. Good luck man.
1 - 9 of 9 Posts