Can I adjust headlights myself?

Dear Car Talk

Dear Car Talk | Feb 01, 2003

Dear Tom and Ray:

I just put new headlights in and was wondering how to adjust them. My car manual tells you where the adjusting screws are, but it does not tell you how far to turn them. I know that I could go to a mechanic to have them adjusted, but is the chart that mechanics use top-secret, or do they have a deal going with Detroit to not release the chart? I would hate to pay $15 every time I need them adjusted. My car, by the way, is a 1988 Toyota Celica GT with the cute pop-up headlights. Thanks. -- Andy

RAY: Well, here's what my brother does. He adjusts both headlights up and to the left as far as they can go. Then, every day he moves them a quarter turn down and to the right. And when people in oncoming vehicles stop giving him the finger and cursing at him as they pass, he figures he's getting pretty close.

TOM: Actually, if all you did was change the bulbs, you shouldn't have to readjust the headlights at all. The adjustment screws are totally separate from the installation hardware, and you don't have to touch them when you put a bulb in. So unless you already turned the wrong screws, Andy, the headlights should still be fine.

RAY: Oh, you DID turn the wrong screws? You knucklehead. Well, in that case, your headlights will need to be adjusted. And unfortunately, there's really no way to adjust them accurately without the chart and the perfectly flat floor that many service stations have.

TOM: You can do an approximate job by taking two measurements. First, measure the distance from the ground to your headlights. Then measure the distance between the headlights (always measure from the center of the bulb). Next, measure and mark the same spots on a wall or garage door with two pieces of electrical tape. From 25 feet away, on a perfectly flat floor, your low beams should point slightly below and to the right of those marks. So, if your marks on the garage door make crosses, the most intense part of the beams should be just inside the lower right quadrants. You want to err on the side of NOT blinding oncoming drivers.

RAY: But as we said, that's only an approximation. The real chart is designed to set your low beams so that you can see about 100 feet from your car, which gives you just about enough time to react to something in the road. And we recommend that you let a mechanic set the lights for you. It's inexpensive, it takes five minutes, and some guys will even do it for free during your annual inspection or another service visit.

TOM: Having them checked once a year and adjusted, if necessary, is a good idea. They can go out of adjustment over time, due to road vibrations or just the aging of the car's suspension system. And can't we all benefit from seeing better at night?

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