2003 530i Sport Headlight Adjustment - How

Fudman said:

There are two plastic allen screws on the top of each headlight (L & R). One (outside?) moves the low beam left or right. The other (inside) moves the lowbeam up and down. I can't remember which screw worked which direction.

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PJB. said:

The "plate" that holds the high and low beams is held on the bottom by one off-center support, and at the top corners by the adjusters. One needs to turn both screws the same amount in order to produce a purely up-and-down motion. Twisting just one side will move the lights left-and-right in additon to up-and-down.

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Fudman said:

Not per Bentley (630-5) and my experience. Bentley says the 6mm outboard adjuster is for lateral movement and the inboard adjuster is for vertical movement. My experience is that the adjusters work for the low beam only. BTW, Bentley says there are horizontal knobs that will also adjust the beam but I don't recall them being there and always used the 6mm allen wrench.

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Fudman said:

PJB:
I stand corrected. Nice info. Appreciate you digging that up. Thanx!

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PJB. said:

I'm not knocking you, but the Bentley isn't always right! Here's one example of a Bentley error (8th picture):

http://forums.bimmerforums.com/forum/showthread.php?t=835680

Now back on topic...

A while back I gutted both 1996-2000 xenons and 2001-2003 xenons and got a really good idea of how they work, found all the adjusting documents I could find, yada yada yada. There's some conflicting information and yes, the outer adjuster is MOSTLY for lateral aim and the inner is MOSTLY for vertical aim, but take a look at how I described the configuration of the adjusters and you'll see that the degrees of freedom are not purely up/down and left/right, but rather in a diagonal fashion. The light looks like the following diagram:

We're looking at the passenger's side light from the front of the vehicle. I mentioned that two adjusters are on top and there is a ball and socket joint on the bottom. However, if you look at the lights carefully you'll notice that the socket is not positioned directly under the midpoint of the line between the two adjusters; the socket is oriented closer to the inner adjuster. This is what gives the outer adjuster the ability to swivel the "plate" that holds the lights to the left or right. Being a triangular setup, any left or right adjustment via the outer adjuster will additionally move the light down or up, and by the same mechanics, any up or down adjustment of the inner adjuster will also result in some left and right movement. Both adjusters need to be turned an equal number of times to eliminate the possibility of turning the light right or left.

Within my searches I've never found a definitive document concerning left/right adjustment of the lights - only vertical and only to achieve the negative 1% slope required. The following is a technical memorandum from BMW. The wording highlighted in red should be of interest in this thread, and information put out by BMW should supercede the Bentley manual:

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bluebee said:

Pending results to the answer to this question ... if the answer is "diagonal", then here is my modified 12-step proposed headlight alignment procedure (please fix as needed!).

(1) Inflate tires properly, tank 1/2 full, typical driver in seat.
(2) Find a wall at least 4' high abutting about 35' of level drivable ground
(3) Obtain two 6mm allen wrenches (each headlight's two adjusters must be turned simultaneously an equal number of turns in the same direction)
(4) Find a small self-standing or clipping light to see under the hood.

(5) On a dark night, park just close enough to the wall to fit your body in between as you string the tape along the wall.
​

(6) Mark a 10' horizontal line with tape on the wall at the headlight midpoint; the result should look something like this:
----------------------------------------
​

(7) At each headlight centerpoint, mark a vertical line with tape on the wall to make a plus sign (one for each headlight center point); the result should now look something like this:
--+---------------------------------+--
​

(8) Back the vehicle until the headlights are 25 feet from the wall and perpendicular to the wall.
(9) Switch the low beam on (both high & low adjust together for each headlight).
(10) Wait about 1 minute as the Xenons do a calibration run which takes about 30 seconds to complete.
(11) Cover one headlight with an opaque blanket or towel so that only one light is being aimed.
(12) Chant "Lateral:lateral, Medial:vertical", three or four times (or until at least the lateral:lateral part sinks in). This is because the lateral (outside) adjuster MOSTLY moves the headlight laterally (i.e., side to side); in actuality, it moves the headlight aim diagonally, but mostly horizontally. Likewise, the medial (inside) adjuster MOSTLY moves the headlight vertically (i.e., up and down); in actuality, it moves the headlight aim diagonally, but mostly vertically.
​

(13) Using both 6mm allen wrenches in place on one headlight, twist both adjusters an equal number of turns in the same direction such that the brightest area moves diagonally to about 2" below the horizontal reference tape and to 2" to the right of the vertical reference tape (i.e., the plus sign) for each side respectively (the spec is 2.1 inches/52mm +/- 1.3 inches/33mm).
(14) As a doublecheck, switch on the high beams (the respective alignment should remain the same).

The result should look something like this:
--+----------------------------------+--
-----*----------------------------------*

PS: It's confusing to me how BOTH adjusters work in tandem diagonally; but that's what the BMW E39 headlight aiming instructions seem to indicate.

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