I just installed new headlights and I need to check and adjust how they are aimed.

I've read the shop manual and this old thread - https://www.s2ki.com/forums/s2000-un...-352248/page3/.
Billman posted a little picture there that serves to show that both lights should be adjusted to the same height,
which I understand. I've also read the interesting write up at modifry.com here: https://modifry.com/freebies/old/zenon/index.htm.

Each headlight has a sharp cut off so each light shines at two distinct heights, slightly lower on the left, slightly higher on the right. My understanding is that both headlights should be set to shine at the same heights. (see Billman drawing). So the height of the left and right cut off lines generated by each headlight should match.

My question relates to how you determine what height should be used. At 25 feet, both lights should shine about 2 inches lower than the height of the center of the hid bulb at the car. My question is this, is it the lower, or the higher, cut off line that should be used to measure the 2" distance below the HID center height? The shop manual depiction of this is unclear because the depiction of the beam is not consistent with the actual cut off lines that each HID throws. But to me, the picture in the shop manual suggests that you use the lower cut off line to measure the 2". Modify interprets it to mean that you use the higher cut off line to measure the 2" distance. Billman's drawing does not address this question.

Which is it?

 

Too late now but when I have changed headlights for my other cars, I mark the beam pattern on paper or cardboard before the change. Then I just adjust the new ones to match.

 

Well, the old ones were never right anyway.

 

Always measure beam pattern height on the lower step of projectors. The higher step is supposed to be higher to light up the side of the road and signs.

As well the steps should line up at 25ft

There shouldn't be two

_/``_/````

The / part should line up together to make it appear as one

___/`````

In order to achieve this, the passenger side beam should be straight, and the driver side beam should be adjusted off-road to point slight to the passenger side.



Right

Wrong, you should only see double if you are not 90° perpendicular to the wall.

 

Is it possible to adjust the headlight left to right?

EDIT - Seems to me that if the aim of two beams are converging then you will get a match in the cut off like is depicted only at one particular distance, depending on the angle of convergence. Close up and the cut from the left bulb will appear to the left of the right beam. At one distance they will match. But, far away and the cut from the left bulb will appear the the right of the right beam cut. No matter how you adjust the beams laterally this will always be the case. Right?

When I get some time I think I am going to adjust mine so that both beams are at the same height and the lower cut off (the one to the left) is set about 2" below the height of the center of the HID height at 25 feet from a wall. If that seems to present problems for oncoming traffic, or cars I am following, I'll lower them. But, our cars are so low anyway that I doubt there will be problems adjusted this way.

I just ran across this:
And this:
And this: