Aiming Headlights

Although the principle of aiming headlights is the same in the majority of cases, the legal rules can differ from region to region. Be sure to check the requirements for your location. If you are unsure of what these are, ask your supervisor. Some manufacturers may suggest that the headlights be aimed on high beam, others on low beam, and in cases of separate high and low beams, both beams may need to be aimed independently. The manufacturer may also suggest that a load be placed in the vehicle, to simulate the ride height of the vehicle when it is travelling down the road. Headlights are typically aligned both vertically and horizontally so that as much of the road is illuminated as possible, without blinding oncoming traffic. Some vehicles have headlights that adjust automatically; do not try to adjust those unless you are diagnosing a fault in the system.

When aiming or aligning headlights, there are a couple of possible methods to utilize. The first, while no longer commonly used, involves an on-vehicle headlight aligner. This method was used extensively on sealed-beam head-lights. The aligners are calibrated to the floor at the point where the front and rear wheels contact the concrete. Then the aligners are installed on the headlights with a built-in suction cup, which holds them in place. The aligners use a set of mirrors that can be calibrated to local regulations so that the headlights can be aligned properly.

With the introduction of aerodynamic headlights using removable halogen bulbs, off-vehicle headlight aligners became more popular. These aligners sit in front of the vehicle after being calibrated for the floor slope and orientation with the vehicle. With the headlights on, adjustments can be made by following the instructions on the aligner. Refer to the manufacturer’s information for specific information regarding headlight aiming.

To aim headlights, follow the steps in Skill Drill 39-4:

1
Make sure the tires are inflated properly, the wheels point straight ahead, and there is no extra weight in the vehicle.
2
Move the vehicle into the correct position in relation to the headlamp aligner unit following the equipment manufacturer’s instructions.
3
Calibrate the aligner to any floor slope and for the vehicle being aligned. If this is not performed accurately, the headlights will not be aimed correctly. (Photo 1)
4
On the types of aligners that require the headlights to be on during alignment, turn the headlights on to a low beam setting. The center of the illuminating beams should be in the lower right quadrants of the chart or wall markings or as specified by the manufacturer. (Photo 2)
5
The high beam should be centered, falling on the intersections of the horizontal and vertical marks or as specified by the manufacturer.
6
If necessary, locate the adjustment screws on the headlight and turn them so the lights point to the correct places, or bubbles on the levels are centered, depending upon which type of aligner equipment you are using. Diagnose the cause of brighter-than-normal, intermittent, dim, or no-light operation to determine necessary action. (Photo 3)
SKILL DRILL
39-4
Aiming Headlights
24118 CH32 SKDSD09 05
1
Make sure the tires are inflated properly, the wheels point straight ahead, and there is no extra weight in the vehicle. Position the vehicle correctly in relation to the headlamp aligner unit following the equipment manufacturer’s instructions. Calibrate the aligner for any floor slope and for the vehicle being tested.
24118 CH32 SKDSD09 05
2
On the types of aligners that require the headlights to be on during alignment, turn the headlights on to a low beam setting. The center of the illuminating beams should be in the lower right quadrants of the chart or wall markings or as specified by the manufacturer.
24118 CH32 SKDSD09 05
3
The high beam should be centered, falling on the intersections of the horizontal and vertical marks or as specified by the manufacturer. If necessary, turn the adjustment screws on the headlight so the lights point to the correct places or bubbles on the levels are centered, depending on the type of aligner equipment you are using.