i cant adjust my headlights

[94_325is]

i adjusted the headlights using the 2 "knob" thingies that uses an Allen key. one for adjusting left-right and the other for up-down. i even used the 3 bolts or whatever that are directly on top of the plastic lens. i adjusted them but a few days later both lights start pointing towards the passenger side(left). how come they wont stay adjusted?

[Russell328is]

The vertical knob is geared so that it moves a horizontal knob that sticks into the back of the headlight casing. Check to see if you can pull the horizontal knob in and out with your hand. If so, it means you screwed it out completely, and it was loose when you drove around so pulled out, which I think moves it to the left. I've done this before. Just screw it back in and you'll be fine. Then, next time you adjust your lights, do it against a dark white wall at an appropriate 2 or 3 carlength distance and you'll get it just right.