How to Adjust Car HeadlightsHave you ever been blinded by someone elses headlights, or noticed that your own headlights are not illuminating the road directly in front of you? If all you can see is the foliage on the side of the road, or oncoming drivers are constantly flashing their high beams or honking their horn at you, most likely your headlights are misaligned, and giving those other drivers an eyeful. They're easy to adjust with a few measurements and a screwdriver. See Step 1 to get started.
Level your car. Start by removing any excess weight from the trunk of the car. Also, ensure that the tire pressure in all tires is at the manufacturer's recommended levels. If possible, have somebody sit in the driver's seat, and that the gas tank is half-full. As well as this, check that your headlight aim adjustment wheel (if fitted) is at the zero position.
Position your car. On level ground, park 10 to 15 feet from a dark wall or garage door, with the front of the car aimed at the wall. A paved parking lot or level driveway is best.
Bounce the car a couple times on all four corners, to make sure the shocks are leveled.
Measure the distance to ground of both headlights, to ensure that the suspension itself is level.
Turn the headlights on. Do not use your high beams or fog lights. Mark the horizontal and vertical center lines of the headlight beams with masking tape to make two Ts on the wall or garage door.
Make sure the lights are level. Place a carpenters level between the two marked center lines to see if they are even. If they are not even, use a tape measure to measure how far up the wall the lower mark is and lower the other center line marker to the same height. These center lines should be no higher than 3.5 feet from the ground.
Back your car 25 feet from the wall or garage door. Turn off the headlights. Remove the trim ring from around the headlights and locate the adjusting screws. These screws are typically found adjacent to the headlight, though some manufacturers put the screws in the engine compartment, behind the the headlights. The horizontal adjustor and the vertical adjuster should be marked.
Always defer to the specs in the owner's manualsome manufacturers recommend different distances for proper adjustment.
There should be one screw at the top of the headlight to adjust vertically and another screw to one side of the headlight to adjust horizontally, though some cars may feature adjustment bolts rather than screws.
Adjust each headlight separately. Block one with a sweatshirt or other object while adjusting and testing the other, since the light-bleed can make it difficult to distinguish one from the other. Have a helper sit in the driver's seat while you do the adjustments, to turn the lights on and off while you make the proper adjustments.7.
Turn the upper screw or bolt to adjust the vertical field. Clockwise turns should raise the lights, while counterclockwise turns should lower the lights.
Turn the headlights on after adjusting and look at the light pattern on the wall. The top of the most intense part of the beam should be even with, or just below the center of the line of tape you made.
Turn the side screws or bolts to adjust the horizontal field. Now, you'll do basically the same thing with the right-left adjustment. The majority of the intense part of the beam should be to the right of the vertical line.
Test your alignment on the road. Take your car out for a test drive to make sure the headlights are adjusted properly. Readjust if necessary by repeating the above steps.
Here's how to correctly adjust your headlights
Headlights are some of those things that everyone needs to use, every time its dark. Most of the time driving at night and using your headlights is a worry free and simple operation, that is until someone appears behind you with their headlights blinding you via your rear view mirror.
When this happens its not only annoying but dangerous and distracting for drivers in front of you and oncoming traffic.
So what causes this to happen? Well there could be a few potential reasons; a front end impact could alter the angle of the headlights or crack the casing which holds the light in place, time and vibrations may cause the angle to change and so could replacing the whole headlight assembly.
However, the most likely cause of your new possum spotting headlights is because the rear of the car is loaded up, either with gear in the boot or a trailer on the back. If carrying heavy loads or towing a trailer is a common occurrence then the only viable solution may be a set of load levelling-levelling shock absorbers.
If youre not weighing down the back of your car but youre still lighting up the trees rather than the road, fear not as adjusting the headlights is a fairly simple process;
Adjusting your lights from the dash:
In some newer cars, the headlights can be simply adjusted by using a button or knob located near the right hand side of the dash for the driver. However if your vehicle doesnt have a button or knob use the steps below.
Adjusting your lights from under the hood:1. Park the car on level ground 7.5 metres (use a tape measure) from a flat vertical surface, your garage wall will work.
2. Open the bonnet and look at the back of the headlight casing, on most models there will be two adjustment screws/bolts on the rear or top of each headlight-locate them and grab the right tool in order to turn them (check the owners manual to be sure theyre the right ones).
3. Cover one headlight with a towel or similar and turn the headlights on (you may want to have the engine running if your battery isnt new).
4. One screw will adjust the headlight up/down while the other will adjust left/right keeping your eye on the beam on the wall slowly turn one of the screws to determine which direction its adjusting, if its not the way you want turn it back to the original location and use the other screw.
5. Ideally the beam on the wall should be no higher than the centreline of the headlight with the area of most intensity directly in front of the headlight casing(use your tape measure here again to measure from the ground to the middle of your headlight and do the same on the wall when adjusting you can even put a mark on the wall to help you aim).
6. In Australia you want the most intensity from the left hand headlight on the road shoulder, and as such the top of the headlight beams should display a pair of laidback L shapes on the wall as seen in the illustration.
7. Repeat the procedure for the other headlight.
If your headlights dont appear quite so simple to adjust, it is best to take the car to your local Motorama Service Departmentfor a professional to quickly sort them out.
How to Adjust Your Headlights
Need to adjust your beams? Here's out quick-and-dirty guide to ensuring your headlights are aligned to shine on the road rather than in the eyes of oncoming drivers.
By Paul Weissler
January 13, 2005 12:00 AM Text Size: A . A . A
If you're on vacation and the back of the car is loaded with hunting and fishing gear, maybe even a large catch, plus other "road hugging weight," that's probably the cause of your headlight problems. That extra weight pushes down the rear enough to tilt up the front and the beams. If you periodically carry heavy rear-end loads as part of your lifestyle, the only real cure is a pair of load-leveling air shocks.
However, in most cases, the headlamp aim has gone off, and simply needs readjustment. Why? Replacing the front headlamp assembly certainly could do ita stack-up in manufacturing tolerances could affect the way the assembly seats. Even a new halogen bulb might be responsible, although that's less likely.
And headlamp aim doesn't last forever, particularly if the assembly loosens and shifts or if the vehicle's suspension sags.
Many models (particularly Hondas and Acuras) have a bubble level in the headlamp assembly to check vertical aim. This does make it easier to diagnose unwanted tilt. Just make sure the tire pressures are at specs and the vehicle is on level ground (check with a carpenter's bubble level on a flat surface). Have the fuel tank half-full and someone in the driver's seat. Reposition the car if necessary to get a level location. Jounce each side of the front end of the car up and down a few times to settle the suspension. Measure from any convenient fixed point on each of the headlamps to the ground; the measurements should be within 1/2 in., indicating the suspension is not sagging excessively at either side. Then, locate the vertical adjuster and turn it to center the bubble.
Even if your headlamps have a bubble level, it's strictly for vertical aim. It's less common, but still possible, for the headlamp aim to be off horizontally. The left headlamp may be aimed at the oncoming cars instead of straight ahead or slightly to the right, and that's equally annoying. But you might be in luck. Some cars with a bubble level for vertical aim also have an alignment indicator for horizontal aim (here again, Honda and Acura). You just have to turn the adjuster to reset the indicator.
On most vehicles, however, it isn't quite that simple because there is no bubble level or horizontal alignment indicator. All you have are the adjusters, and in some cars, only for vertical aim. If the horizontal aim is off and there is no horizontal adjuster, the issue is mechanical alignment of the housing in the front end, and all you can do for this is shim one side of the housingit's a cut-and-try operationuntil the alignment of the beam is acceptable.
Without indicators in the housing or professional headlamp alignment equipment, you have to look at how the beams strike a vertical flat surface, and if they're off, make adjustments.
Proper headlight aim is critical. Check aim with a driver in the car and a full tank of gas. The low-beam cutoff (a) should be slightly below the center of the lens (b) to keep glare out of oncoming traffic and reduce the light reflection that occurs during rainy or snowy weather. The bend in the cutoff should be slightly to the right of the center of the lane, for the same purpose. This will illuminate the road surface in front of the car, as well as the curb area to the right.
There is a standard procedure, using a flat and level driveway facing a gray or dull white wall that is free of any source of peripheral light (perhaps the back wall of your garage, interior lights off). The open space on the wall should be at least the width of the vehicle plus an extra 2 ft. per side. Check the tire pressuresthey have to be right. Confirm that the car is on level ground by using a good carpenter's level on the side of the vehicleon an SUV try the roof, and on most cars, the door frame. Park the car so it's exactly 25 ft. from the wall to the face of the headlampsdon't estimate. Some exceptions include Toyota, which specifies 10 ft., Pontiac GTO at 15 ft., and Chrysler, which specifies 33 ft. on some models. However, the 25-ft. procedure should produce satisfactory results for most vehicles. Use a tape measure in any case.
Check the suspension ride height side to side to make sure there's no excessive suspension sag.
Now comes a lot of very careful measuring. First, identify the physical center of each low-beam headlampwith today's multilamp housings, actually turn on the lamps to be sure you have the right lamp. Some headlamps have a small dot or circle at the center. Make a tape cross over the center of each lamp, and a vertical tapeline down the center of the windshield. Using a tape measure, make the corresponding alignment marks on the wall.
For this part, you might be able to measure at the wall from the ground up, but it's easier (and good for a double-check) to bring the vehicle very close to the wall. Then, again with tape, transfer the locations to the wall (perhaps using a bubble level to span the gap between vehicle and wall, to ensure an accurate transfer). On the wall, make the tapelines very widebasically a single horizontal line for both centerlines of the headlamps, and a vertical tapeline for the centerline of the vehicleand long enough so that it's easy to line up the vehicle and for the lines to form a cross. Make the centerline vertical crossing tapes for the headlamps themselves about 2 ft. long on the wall. The accuracy of any adjustment is only as good as the reference points. In fact, it's a good idea to lay strips of tape on the ground at the midpoints of the rear tires, so that when you back up to the specified distance from the wall, you can be sure you've maintained the overall alignment of the vehicle to the wall. The tape on the windshield and the centerline of the wall also should be useful visual aids.
Next, locate the headlamp adjusters. If you're a veteran Saturday mechanic, this may sound like "are you kidding," but we're serious. The adjusters used to be on the external rim of the sealed-beam headlamp assemblies. But with the change to quartz halogen bulbs, they're on the back of the headlamp assemblies. Some makers simply buried or eliminated the horizontal adjusters. So find out what you have, and where it is.
We've seen a number of "mainstream" cars (yes, that includes General Motors) with the vertical adjusters at the bottom of the housings. It's not a problem if there's nothing in the way of the adjuster, but we've seen the battery, coolant reservoir, even the antilock brake actuator behind it. You may have to remove what's behind the housing to confirm the location of the adjusters, or even to be able to put a tool on the adjuster.
Once you locate the adjusters, back the vehicle up to the 25-ft. mark and turn on the low beamsdo this on a dark night. Have a passenger sit in the driver's seat. Block the light from one headlamp, but not by covering the headlamp assembly (it could get hot enough to melt the plastic lens). A kitchen chair with your jacket draped over the back a couple of feet from the bumper works well.
Look at the light pattern on the wall. Vertical aim: The top of the most intense part of the beam should be at or below the centerline of the headlamp horizontal tapeline. Horizontal aim: Most of the intense part of the beam should be to the right of the vertical centerline of the headlamp assembly.
Specifications vary, and if your state inspection system checks headlamp aim, it may have its own specifications, which, of course, you should use. Otherwise, observe manufacturer's specifications (in the lighting sections of service manuals) if available. With today's brighter headlamps, you want to be as friendly as possible to oncoming cars without affecting your ability to see ahead.
Some examples of factory specifications on typical vehicles (measured below the horizontal centerline of the headlamp): zero distance on General Motors, less than 1/2 in. on Toyota (at the 10-ft. distance), less than 1 in. to slightly more than 3-1/2 in. on Nissan vehicles, and 2 to 6 in. on Chrysler Group vehicles. If you don't have specifications (or a bubble level in the assembly), at least 2 to 4 in. below the centerline at 25 ft. should be acceptable, although slightly more certainly would eliminate any complaints from oncoming vehicles. It may be somewhat difficult to determine the middle of the most intense part of the beam, but there should be very little of the top edge of the overall beam above the horizontal line. The kickup is the part of the pattern where light is projected above the normal cutoff. This is to illuminate objects to the right, such as road signs or pedestrians, without throwing glare onto oncoming traffic.
Have to make adjustments? First jounce each side of the front end to stabilize the suspension, then turn the adjuster a quarter-turn and look. Horizontal aim of the most intense part of the beam may be given in the manufacturer's specifications. If not, a friendly setting for oncoming cars is 2 to 4 in. to the right of the vertical center of the headlamp assembly. General Motors' ultrafriendly setting is to have the left edge of the intense part of each beam flush with the physical vertical centerlines of the headlamp assemblies, and just under the horizontal centerline. Repeat the procedure for the other headlamp, trying to get the most intense part of the beam as close to the adjustment of the first headlamp as possible.
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How To Aim Headlamps and Auxiliary Lamps
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Your headlamps will work as designed only if they are correctly aimed. Improperly aimed headlamps are dangerous, ineffective and illegal. The following procedures will assure correct aim of your headlamps for maximum seeing without unlawful and dangerous glare. Be sure to use the correct procedure for the specific headlamps and vehicle you are working with.
An optical beamsetter is a device that looks a bit like a TV camera. It is wheeled in front of each headlamp on your vehicle, adjusted to height, and the optics within the beamsetter permit highly precise visual aim checking and adjustment. This is definitely the most accurate way to aim lamps, but beamsetters are not yet as common in North America as they are elsewhere in the world. However, more and more optical beamsetters are placed in service all the time, so check around before deciding nobody near you has one. High-end body shops and auto dealer service departments are good bets.
If you cannot find someone who has a beamsetter and will use it correctly, you aren't necessarily out of luck. Fog lamps, driving lamps, and visually-aimable headlamps do not require a mechanical aimer or other machine in order to achieve at least passably-correct visual aim. All ECE (E-code) headlamps are visually aimable, and many newer US (DOT) headlamps can be accurately aimed visually. First, you must determine if your headlamps can accurately be aimed visually. If you have ECE (E-code, European-spec) headlamps, you can aim them visually. If your US DOT headlamp lenses are marked VOL, VO or VOR, they can be aimed visually. If your US DOT headlamps are NOT marked VOL, VO or VOR, they cannot officially be correctly aimed visually and are intended to be aimed using a mechanical aiming device. These mechanical aiming devices are all but extinct, and so you will likely have to do the best you can using a visual method.
To prepare for aiming, the car should have at least 1/2 tank of fuel, weight in the trunk equal to the most frequently carried load (this may be a full trunk, or it may be an empty one, or anything in between), and weight in the driver's seat equivalent to the most frequent driver. All of the tires should be checked when cold to make sure they're at the correct inflation pressure. Jounce each corner of the car firmly (grasp the bumper and push down several times rhythmically) to ensure that the suspension is settled into a normal position.
Find a location that has a vertical wall and enough level ground for the length of the vehicle plus 25 feet (7.5 m). The wall will be used as an aiming screen. You'll need to make marks on the wall, so if it is a wall you're not allowed to deface, use tape. Measure a distance of 25 feet (7.5 m) straight back from the wall, and mark this position on the floor or ground. Align front of the vehicle with this floor mark, and then bring the vehicle straight forward, right up to the wall. Make a mark "V" on the wall directly in front of the center of the vehicle. Good references for the center point include such things as hood ornaments, grille badges and license plate brackets.
Next, make a mark "C" on the wall directly in front of the axis of each lamp. The "axis" is often marked with a dot, cross, bulb type designation or name brand, but if not, it is directly in front of the bulb. There is one axis for each lamp, so a vehicle with four lights will have four axes and a vehicle with two lights will have two, plus any auxiliary fog and/or driving lamps that may be present.
Now, move the vehicle straight back from the wall until the headlamps are aligned with the floor mark. Walk to the wall and make additional marks: Extend the "V" mark with a vertical line downward at least six inches. Next, connect all of the "C" marks with a horizontal line we'll call "H-H". Then, measure downward from each "C" mark that represents the axis of a lamp and place a mark "B" per the following tables.
ECE (European E-code) headlamps
Lamp axis heightDistance to measure downward
Up to 34.5" (80 cm)3" (76 mm)
35" to 39" (89-99 cm)4" (102 mm)
39.5" or higher (100 cm)4.5" (114 mm)
US DOT headlamps marked VOL
Up to 34.5" (80 cm)2.1" (53 mm)
35" to 39" (89-99 cm)3" (76 mm)
39.5" or higher (100 cm)3.5" (89 mm)
US DOT headlamps marked VOR,and mechanical aim low or high/low beam lamps
Up to 34.5" (80 cm)N/A, do not measure downward
35" to 39" (89-99 cm)2" (50 mm)
39.5" or higher (100 cm)3" (76 mm)
US DOT headlamps marked VO,Mechanical-aim high-beam-only lamps,and Driving (auxiliary high beam) lamps
Any mount height (80cm)N/A, do not measure downward
Up to 18" (46 cm)1.5" (38 mm)
18.5" to 28" (47-71 cm)3" (76 mm)
28.5" or higher (72 cm)4" (102 mm)
Connect these two newly-measured points with a horizontal line we'll call "B-B". After you've done all of this, your wall will be marked like this for a system of two high/low beam headlamps:
Or like this for a system of two low- or low/high beam plus two high-beam lamps:
NOTE The visual aim procedure for lamps listed above as "N/A, do not measure downward" does not require the lower B-B horizontal line. Simply connect your +C marks with a horizontal line.
Now draw a vertical line through through the center of each +C point. Do the same with the oV point. These lines make it easier to see the reference marks when you are standing 25 feet away, adjusting the aiming screws on the car. You now have an accurate plot on the wall of the height and separation of the headlamps (but ONLY if your car is level, the ground is level and the wall is vertical!). Note that the "B-B", "C" and "V" designations are for purposes of clarity in this descriptive article. It is not necessary to draw the letters on the wall--just plot the points. Of course, you may use the letters in your aiming procedure if it will help you.
The low beam pattern of a visually-aimable headlamp has a distinct horizontal cutoff. Below the cutoff is bright light. Above the cutoff is dark. The aim is determined by measuring and adjusting the height of this cutoff relative to the reference marks you plotted on the wall.
For European-spec ECE and US DOT VOL headlamps, the cutoff is at the top of the left half of the beam pattern, and it should be lined-up exactly with the B-B line.
For US DOT VOR headlamps, the cutoff is the squared-off top edge of the 'hot spot' (brightest region of the beam) on the right side of the beam pattern, and should be lined-up exactly with the applicable horizontal line per the table above.
For mechanical-aim headlamps, you will have to do your best to place the top edge of the low beam 'hot spot' on the applicable horizontal line per the table above.
These instructions are applicable only to European ECE low beams, because US DOT VOL and VOR headlamps cannot be visually aimed horizontally, and in many cases, cannot be aimed horizontally by any means at all, because no provision for horizontal aim adjustment is provided. [This is because US regulators believe there is no way to define a visual cue, such as a kink in the cutoff, that would allow accurate left-to-right placement of a headlamp beam and that cars will not get in fender-benders that will knock the headlamps out of horizontal alignment. For what it's worth, the Europeans have been successfully aiming their headlamps vertically AND horizontally since 1955. -ed.]
European ECE headlamps have a "kink" or "elbow" at the top of the center of the beam pattern, where the cutoff bends upwards. Adjust each headlamp so that the kink lines up (left-to-right) with the +C mark for whichever headlamp you're working on. The tolerance here is +/- 2 inches of point (c). Slight leftward aim (-1") increases seeing distance down the road, but excessive leftward aim increases glare to oncoming traffic.
Here is what a correctly aimed set of European ECE or US DOT VOL headlamps looks like on low beam:
And here is what a correctly aimed set of US DOT VOR or mechanical-aim headlamps looks like on low beam:
After adjusting a high/low beam headlamp in the low beam mode, do not attempt to readjust it in high beam mode. All high/low beam headlamps are meant to be adjusted on the low beam setting only--the high beam adjustment is correct when the low beam adjustment is correct. If you are experiencing a problem where setting the low beams correctly places the high beams too high, but setting the high beams correctly places the low beams too low, you are dealing with a poorly-designed headlamp.
DRIVING LAMPS & HIGH-BEAM-ONLY LAMPS IN 4-LAMP SYSTEMS
These instructions apply to ECE high beam headlamps, US DOT high beam headlamps marked "VO", and all driving lamps. These must be adjusted so that the bright, center "hot spot" of the beam is straight ahead of the lamp in both the vertical and horizontal planes. Use the intersection of the horizontal and vertical lines at point +C for each headlamp as "cross-hair sights" to center the high beam hot spot, like this:
Make sure to work on one lamp at a time. It is best to disconnect the power to the headlamp you are not working on, so light from the other lamp's beam pattern doesn't mislead your eyes. Also be sure to disconnect or cover the adjacent high/low beam lamp when you are aiming its high-beam-only neighbour.
Fog lamps are aimed using a procedure very similar to that used for low-beam headlamps. The cutoff extends clear across the top of the beam pattern. Simply align the fog lamp so that the cutoff at the top of the beam falls on the appropriate B-B line for the lamp mounting height, as listed in the table above.
Fog lamps produce a wide, bar-shaped beam of light. Horizontal aim is much less critical than it is with headlamps. The fog lamps should be pointed straight ahead, not leftward or rightward.