Headlights, like any other lighting device, can fail due to broken filaments. The front of any truck is the worst possible location for a lighting device since it is subject to impact, extensive temperature change and severe vibrationall of which shorten the life of the light. The front of the truck is also where good lighting is needed the most so its not uncommon to have to replace a headlight during the life of the vehicle.
There are two general styles of headlamps, the sealed beam and replaceable bulb type. The sealed beam type of headlamps are used on older vehicles that were built through the 1980s. The sealed beam is so named because it includes the lamp (filament), the reflector and the lens in one sealed unit. Sealed beams are available in several sizes and shapes.
The replaceable bulb is the newer technology. All vehicles covered by this information use the replaceable bulb, or composite headlight bulb. Using a small halogen bulb, only the lamp is replaced, while the lens and reflector are part of the body of the car. This is generally the style found on wrap-around or "European" lighting systems. While the replaceable bulbs are more expensive than sealed beams, they generally produce more and better light. The fixed lenses and reflectors can be engineered to allow better frontal styling and better light distribution for a particular vehicle.
It is quite possible to replace a headlight of either type without affecting the alignment (aim) of the light. Sealed beams mount into a bracket (bucket) to which springs are attached. The adjusting screws control the position of the bucket, which in turn aims the light. Replaceable bulbs simply fit into the back of the reflector. Separate adjusting screws aim the lens and reflector unit.
Take a moment before disassembly to identify the large adjusting screws (generally two for each lamp, one above and one at the side) and don't change their settings.
REMOVAL & INSTALLATION
- With the ignition switch OFF and the headlamp switch OFF, raise and prop the hood.
- Locate the headlight bulb, then unplug the connector for the bulb.
- Turn the plastic cover counterclockwise, and then remove it.
- Remove the rubber cover.
- Release the bulb retaining spring, and then carefully remove the bulb from the headlight lens.
- Align the tabs of the bulb with the cutout of the mounting hole and install the bulb.
- Install the retaining spring, and then attach the rubber cover. Make sure the rubber cover is snug on the connector and the headlight body.
- Install the plastic cover with the "ON" mark facing upwards. Turn it clockwise, and then insert the connector.
- Aiming is usually not necessary after replacing these types of bulbs.
AIMING THE HEADLIGHTS
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 that is equipped with headlight aiming tools. Improper adjustments may be both dangerous and illegal.
Because the composite headlight assembly is bolted into position, no adjustment should be necessary or possible. Some applications, however, may be bolted to an adjuster plate or may be retained by adjusting screws. If so, follow this procedure when adjusting the lights, BUT always have the adjustment checked by a reputable shop.
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 that 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 high beam and mark the center of each light's high beam. A short length of masking tape that 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.