[LPM911]

Was driving the M3 the other night and noticed that the headlights seemed to be exceptionally low. So low, that I ended up having to drive around with my brights on just to see anything that wasn't 6' in front of the car. Internet said first thing to check was the plastic sensor arms.

Here is the front (passenger side):




Here is the rear (passenger side):






The sensors look fine to me. Tomorrow I will try to get my computer connected and see if anything shows up in the diagnostic software. Not sure what else to check from here.

When I start the car with the headlight switch in auto, I can see the beams adjusting up and then down. But then they just stay down. So I don't think its the motors that controls them.

These have been perfectly fine the last 7 years of ownership, so I'm hesitant to just adjust the beam using the knobs on the lights themselves before getting a good diagnosis on why they all of of sudden are adjusting themselves all the way down.

Anyone ever had a similar issue? What should I look for next?

[cmartin]

Can you disconnect the sensors? I remember working on these headlights but its been a long time, that keeps them fixed. Is there also a rear sensor, IIRC on 1 side?

[HughA44s]

I am not sure I can help much here as I have not had this problem however e46fanatics and m3forum is always a good place to start. Is there a negative testings scheme you can Use: ie disconnect the sensors one at a time and see if it acts different.

[ItalyChicken]

Just read the full text, and if you see them both adjust up and down on start, the following wouldnt apply. Are you sure the headlight adjusters are fine? On the E39s it was common that the headlight adjusters which are inside the headlight housing would get brittle and break. This would cause the headlights to point down all the time. You can tell if they're broke if you jiggle where the headlight lamp goes into the lense, if its firm then the adjusters should be fine, but if there's a lot of play then you know they're broken. I didn't think this problem existed in the e46s but if the adjuster sensor has its linkages Id check the headlight.

[roundel]

Tommy suggest the reset procedure. Unfortunately I do not know what this means.

[LPM911]

Rear sensor pictures are there in the original post. The plastic arms on both are not broken which is apparently a common issue.

Researching on the all the BMW forums as well, which is where I found out about the sensors to begin with. But for the most part, that's all they suggest thus far.

Haven't had a chance to hook up to computer systems and see if anything is reporting faulty. But I'm betting the sensors are going to say they are bad.

As for the motors themselves, I'll test again but when starting the car with headlights in auto. I seem them go through the self test which involves going up and down to test the range of motion. Then they just drop.

Reset procedures?

[roundel]

Reset procedures?


Need a scan tool apparently.

[BlackTalon]

Didn't Pari have a gif avatar showing headlights trying to self-level?

[LPM911]

Replaced sensors. Looks like things are back to normal but need a nighttime drive to really test.

Part numbers:
37146784696
37146784697

[Trak Ratt]

Originally Posted by BlackTalon

Didn't Pari have a gif avatar showing headlights trying to self-level?

Just curious but how is this helpful?