Step 1. Test all the lights so you know which one has burned out.
High beams? Low beams? Running lights? You might as well check the taillights too, while you’re at it.
Step 2. Buy your headlight bulb replacements.
Buying your headlight replacement part isn’t hard. Go by your local auto parts store or shop online for headlight bulbs that fit your vehicle. Depending on the age and make of your car, the replacement bulbs might be halogen or xenon. Make sure the bulbs you buy are the right type: high beam or low beam. And buy two, because it’s best to replace both bulbs at the same time. Otherwise, you’ll have one dim and one bright headlight, and that’s a little weird.
Step 3. Open the hood and locate the rear of the headlight.
To change a headlight bulb, you have to sneak up from the rear (don’t try to pop the headlight cover off the front of your car). You’ll see an electrical connector sticking out of the back of the headlight. Unfasten it carefully. Some car models might require you to remove the entire headlight assembly, which may be held in place by screws or mounting pins.
Step 4. Locate and remove the old headlight bulb.
This can be tricky. “Often the headlight bulb is squished in between a million other parts that are bigger and more imposing and there the little bulb sits, just taunting you,” Jalopnik says. Once you’ve located the bulb, rotate it and pull it out.
If you’ve been having problems with condensation in your headlights, you might as well tackle that problem now, too. You can take out the entire headlight assembly and dry it with a hairdryer or silica packs.
Step 5. Install the headlight bulb replacement.
When you take the new headlight bulb out of its packaging, wear gloves, or handle it with a tissue or cloth. Even a tiny smudge of finger oil can create a hot spot on the glass, causing it to burn out faster. Push in the new bulb and turn it to lock it in place. Refasten the electrical connector and test the bulb. Look good? Don’t forget to replace the other headlight bulb while you’re at it. Now, you know how to change a headlight bulb!
Step 6. Adjust the headlight beams, if needed.
Since you’ve already got the hood up and a little engine grime on your fingers, check to that your headlights are aligned. Adjusting your headlight beams requires some care;
Make sure your tires are all properly inflated.
Park the car on a level surface, 25 feet from a wall or garage door.
Make tape marks to indicate the center of each headlight.
Measure the distance from the beams to the ground.
Each car manufacturer has specific specs on how to measure and align the headlights. If the aim’s a little off, you can use the vertical and horizontal adjusters on each headlight housing to fix it.
Sound tricky? You can also go to your mechanic for a headlight alignment. Just don’t ignore the problem, especially if you have HiD (high-intensity) xenon bulbs. These can blind other drivers if they’re not properly aligned.
