BMW E39 xenon headlight leveling not working
Why do the E39 xenon lights aim too low or shake?
The most common cause is broken plastic adjuster pins or rods in the sealed headlight unit. If they wobble freely when you test the bulb holder, they are broken. On pre-facelift cars (8/2000 and earlier) the head of the adjusting screw can also be broken.
What else can be wrong if the adjustment does not move?
Check the adjusting motor connector, because a broken locking clip can let the connector come loose. If the adjuster pins are intact, the fault can be in the level sensor. Read the fault codes before replacing the sensor, and replace the sensor mounting screws at the same time.
Can the adjuster pins be replaced?
Yes, and new parts are available. On the pre-facelift sealed unit the replacement is easier. The glass of the facelift sealed unit is glued, so the job is more demanding. After replacement the lights must be aimed mechanically if needed, if the front or rear ride height has changed.