Here's a general approach, but always consult your owner's manual first. It will provide specific instructions and diagrams for your exact model and headlight configuration.
General Steps (May Vary):
1. Locate the Adjustment Screws: Open the hood. Behind each headlight assembly, you'll find small screws or knobs. These are usually either:
* Vertical Adjustment: Controls up and down aim.
* Horizontal Adjustment: Controls left and right aim. This is less common and often only needed if one headlight is significantly off-center.
2. Access the Screws: This is the tricky part. Sometimes the screws are readily visible. Other times, you may need to:
* Remove parts of the wheel well liner: To gain better access.
* Remove the headlight assembly (partially or fully): This is more involved and may require specialized tools. Consult a repair manual if you attempt this.
3. Adjust the Screws: Use a small flat-head screwdriver or the appropriate tool (your owner's manual will specify). Generally:
* Turning the screw clockwise raises the beam.
* Turning the screw counter-clockwise lowers the beam.
For horizontal adjustment (if applicable), turning clockwise usually moves the beam to the right, counter-clockwise to the left.
4. Test the Adjustment: After making adjustments, test the headlights on a wall or level surface at a distance of about 25 feet. Look for the cutoff line of the beam. The beam should be level and not too high or low. Repeat steps 3 and 4 until you achieve proper alignment.
Important Considerations:
* Proper Alignment is Crucial: Improperly aimed headlights can cause glare for oncoming drivers and reduce your own visibility.
* Professional Assistance: If you're uncomfortable working on your vehicle, take it to a qualified mechanic or auto repair shop.
* Level Ground: Ensure your truck is parked on level ground for accurate adjustment. A sloped surface will give you inaccurate results.
Again, your owner's manual is the best resource. Find the section on headlights or lighting systems. It will have diagrams and specific instructions for your 2004 Chevy Silverado. Without knowing the specific trim level and headlight type, this is the most general guidance possible.
