Disconnected headlight vertical sensor
When the E39 M5 was first introduced in North America in 2000, it was a $70,000+, top of the line BMW sedan. As such, it came with a list of standard features that were options on lesser models.
One of those standard features was Xenon headlights with an auto adjusting feature, which was fairly new at the time. The level of the headlights is adjusted based on how level the car is, for example aiming lower when traveling up a steep hill. This is done mostly to keep the light out of the eyes of oncoming drivers.
I noticed right away when I bought the car the headlights do a little dance when turned on, dipping down and then swinging up into position. That’s the last I thought about this feature, until I noticed this weekend it was no longer happening. The lights were not moving upwards, and were pointing too low towards the ground.
A little searching on M5Board uncovered a case of unintended BMW consequences. The auto adjusting headlights sensor sits on the right front control arm of the car, right next to the thrust arms I just had replaced a few weeks back. I figured that wasn’t a coincidence, something probably happened to the sensor during the replacement of the front suspension pieces.
Hollin Hall Automotive was very understanding and accommodating when I stopped by and explained the situation. As soon as we put the car up in the air, it was obvious the bracket had come loose and the sensor was no longer attached to the control arm. See the image above. No apparent damage to the sensor itself, just the bracket popping open.
The tip of the bottom piece is supposed to snap through an opening in the front of the bracket. It wasn’t holding, so we put it through and bent it down with pliers. Voila, headlights started adjusting their height again. It was a rare best case scenario BMW repair — simple, quick and easy. And a reminder that when you drive these cars, there is always something new to learn.
Repaired sensor bracket – arrow shows tab bent down