Headlights

Headlight Aiming Procedure

>I need to aim my new headlights. My shop manual calls for an optitcal
>positioning device. Has anyone on this list done this?

I have aimed my headlights on many different cars to my satisfaction in a totally unconventional manner - by looking at the light pattern.

Here is how I do it if you want to try. Instructions assuming you are driving on the right side of the road.

1. Do it at night and get the tools you will need (phillips screwdriver, etc.), a flashlight so you can find the aiming screws, and something to cover one of the lights. On a 928, a small cardboard box works. Just put it over the whole headlight unit. You will probably need to remove the headlight unit cover to make access to the adjustment screws easier.

2. Park the car in front of something vertical like a garge door about 50 feet away, and on level ground. Headlights on dim setting.

3. Cover the passenger side light and aim the drivers light, on dim setting, so the top of the light pattern is about level with, or slightly lower than, the height of the headlights, and so the horizontal brightest part of the beam is angled very slightly to the right.

4. Change the cover to the drivers side light and aim the passengers light so vertically it is slightly higher than the drivers light and horizontally so the brightest part of the beam is a couple feet right of the right side of the car; as if it was illuminating the edge of the road.

5. Now find a dark deserted, level, 2 lane road. You don't want any traffic. You might have to do this late at night. It is also best if it is a little foggy (not a problem in Oregon) so you can see the headlight beam pattern.

6. Headlights on dim. Cover the passenger side light and check the drivers side beam pattern. The brightest part of the beam should be lighting the road directly in front and projecting out to between 100 and 150 feet. The oncoming traffic lane should be nearly dark except for illumination over on the far left side of the road. Adjust the x,y screws to achieve this. You shouldn't have to adjust very far.

7. Cover the drivers side light and check the passenger side light pattern. It should illuminate a bit further down the road than the driver's side and nicely show the right shoulder, ditch, or whatever else is out there. Adjust as necessary to achieve this.

8. Now go drive it and see how well the road is illuminated overall. If you have the dim setting set too high, the brights will be so high you won't be able to see well. Check how the high the vertical illumination is when the lights (on bright) shine on light poles, signs, trees or buildings. If the *brightest* part of the vertical pattern is more than 8 or 10 feet above the ground, then go back and set the dim pattern so it doesn't shine out so far. This is often a compromise to get far out illumination on dim and still see great when on bright.

I have used this method with both US DOT lenses (bad) or the European style, off road only lenses, (good) and It works fine for me. The European lenses are easier to adjust because the beam is better focused and the top of the vertical cutoff is sharp when on dim. It's a little tedious, but I can see well and don't have other drivers flash their lights at me. I use 130/100 watt bulbs in my '86 with off road lenses I bought from, dare I say it, JC Whitney for about $20 each. I did install relays so the normal 928 headlight relay and wiring is not subject to the additional current.

Louis Ott
'86 S auto
'88 S4 5 spd.