The headlights must be properly aimed to provide the best, safest road illumination. The lights should be checked for proper aim and adjusted as necessary. Certain state and local authorities have requirements for headlight aiming; these should be checked before adjustment is made.
Headlight adjustment may be temporarily made using a wall, as described below, or on the rear of another vehicle. When adjusted, the lights should not glare in oncoming car or truck windshields, nor should they illuminate the passenger compartment of vehicles driving in front of you. These adjustments are rough and should always be fine-tuned by a repair shop which is equipped with headlight aiming tools. Improper adjustments may be both dangerous and illegal.
Horizontal and vertical aiming of each headlamp assembly is provided by two adjusting screws which move the housing against the tension of a coil spring. There is no adjustment for focus; this is done during headlight manufacturing.
Before removing the headlight bulb or disturbing the headlamp in any way, note the current settings in order to ease headlight adjustment upon reassembly. If the high or low beam setting of the old lamp still works, this can be done using the wall of a garage or a building:
- Park the vehicle on a level surface, with the fuel tank about 1 / 2 full and with the vehicle empty of all extra cargo (unless normally carried). The vehicle should be facing a wall which is no less than 6 feet (1.8m) high and 12 feet (3.7m) wide. The front of the vehicle should be about 25 feet from the wall.
- If aiming is to be performed outdoors, it is advisable to wait until dusk in order to properly see the headlight beams on the wall. If done in a garage, darken the area around the wall as much as possible by closing shades or hanging cloth over the windows.
- Turn the headlights ON and mark the wall at the center of each light's low beam, then switch on the brights and mark the center of each light's high beam. A short length of masking tape which is visible from the front of the vehicle may be used. Although marking all four positions is advisable, marking one position from each light should be sufficient.
- If neither beam on one side is working, and if another like-sized vehicle is available, park the second one in the exact spot where the vehicle was and mark the beams using the same-side light. Then switch the vehicles so the one to be aimed is back in the original spot. It must be parked no closer to or farther away from the wall than the second vehicle.
- Perform any necessary repairs, but make sure the vehicle is not moved, or is returned to the exact spot from which the lights were marked. Turn the headlights ON and adjust the beams to match the marks on the wall.
- Have the headlight adjustment checked as soon as possible by a reputable repair shop.
The following items should be considered before aiming the headlights:
- Park the vehicle on level ground, so it is perpendicular to and, facing a flat wall about 25 ft. (7.6m) away.
- Remove any stone shields, if equipped, and switch ON the lights.
- Using a Phillips-head screwdriver or suitable hex tool, aim them as follows:
- The horizontal distance between the center of the light beams on the wall should be the same as between the lights themselves.
- For fog lights, the vertical height of the light beams above the ground should be 4 in. (10cm) less than the distance between the ground and the center of the lamp lenses.
- For driving lights, the vertical height should be even with the distance between the ground and the center of the lamp.
- Test to make sure the lights work correctly, and the light pattern is even.
- Pull the connector off the bulb at the back of the headlight.
- Push down on the clip to disengage it.
- Pull the headlight bulb out of the housing. If it is difficult to remove, gently rock it up and down.
- Be careful not to touch the glass part of the bulb. Any oil or dirt even from clean hands will cause a hot spot on the glass during operation and the bulb will break.
- To ease installation, spray some silicone lubricant on your finger and rub it onto the rubber O-ring. Do not spray directly on the O-ring because it will also get on the bulb.
- Install the bulb, snap the clip into place and connect the wiring.
- Open the hood and if equipped with a rubber access cover, remove the cover over the back of the headlight assembly, and then disconnect the electrical connector from the bulb.
- If a rubber seal/cover is mounted around the bulb, disconnect the electrical connector from the bulb, and then remove the rubber seal/cover.
- Once the electrical connector has been disconnected, squeeze the ends of the retaining bracket inward, then pivot the retainer away from the rear of the headlight assembly.
- Grasp the bulb securely and remove, noting the location of the alignment tabs for installation. Allow the bulb to cool before removing it from the headlight assembly.
- Install the new bulb into the headlight housing and squeeze the ends of the retaining bracket inward while pivoting the retainer toward the rear of the headlight assembly. Release the retaining bracket making sure it is fully seated in its retainer.
- The balance of assembly is in reverse order of removal.