On the Toyota Tacoma, the headlight bulbs can be fine-tuned so that they are well-aligned with one another and provide a clear view of the path ahead. If you notice that your headlight beams aren't shining where they should be or that they are pointing in different directions, you can quickly and adjust them yourself. The only real challenge is finding a place that is level and spacious enough to adjust them properly.
Find an appropriate area to align your lights. The ground should be almost perfectly, if not perfectly level. There should be a flat vertical wall against which you can shine your lights and clearly see the boundaries of the beams. There must also be enough room for you to park the Tacoma 25 feet back from this wall.
Prepare the vehicle for normal weight and height conditions. Take everything out of the Tacoma except for the items that stay in the vehicle at all times. Fill the gas tank and make sure the engine oil level is full. Fill all of the tires to the PSI you usually use. Finally, make sure there is someone sitting in the driver's seat during the testing and adjusting process.
When it is dark enough to see the headlight beams, park the Tacoma on level ground, 25 feet back from the wall, facing the wall head-on. Leave the engine running and prop open the bonnet.
Look at the backs of both headlight assemblies. Near the top centre corner of each headlight, you'll find a small round cap. Remove these caps to expose 8mm screws. These screws control the horizontal alignment of the headlights.
Look at the backs of the headlights again, checking the bottom outside corners of the headlights. You'll see identical 8mm screws sticking out. These screws control the vertical alignment of the headlights.
Turn on the headlights and shine the beams against the wall.
Use a measuring tape to measure the distance between the ground and the centre horizontal line in the plastic lenses of the headlights.
Go to the wall and measure the distance between the ground and the centre horizontal line's reflection in the beams of light. If the line on either side is higher on the wall than it is on the Tacoma, the light on that side must be adjusted to point down. If the line is lower on the wall on either side, the light on that side must be adjusted to point up.
Use a 8mm socket wrench to adjust the vertical alignment screws on the headlights, measuring the horizontal lines on the wall as necessary, until the centre lines of both beams are exactly as high as they are on the Tacoma.
Use a measuring tape to measure the distance between the two vertical lines in the centre of each headlight lens.
Go to the wall and measure the distance between the two vertical centre lines' reflections in the beams of light. If they are father apart than they are on the Tacoma, the headlights need to be adjusted toward the centre of the vehicle. If they are too close together, the headlights need to be adjusted toward the outside corners of the vehicle.
Use the 8mm socket wrench to adjust the horizontal alignment screws on both headlights, measuring the vertical lines on the wall as needed, until the distance between the lines on the wall is equal to the distance between the lines on the lenses.
Replace the caps on the top headlight adjustment screws and close the bonnet.