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jcourcoul 06-29-2009 05:28 PM

An HID headlamp DIY adventure...
18 Attachment(s)
Awhile back, I got a lamp out dash warning and discovered that the little pilot bulb in the high beam reflector had fallen off. In that headlamp I had previously discovered a piece of plastic that nobody guessed what it was. Turns out it was part of the autolevelling "suspension" for the headlamp and the little bulb had been pushed out by the reflector because the whole thing was shakin' loose in the wind. This is the story of how I repaired it for now. Tried to document all that transpired in the process so that the pics may be of use for other 'festers having troubles in these areas. This is for a 2006 325Ci coupe, the kind that has sealed one-piece headlamps and the problem lies in the driver's side headlamp. This car came with Bosch/ALS headlamps.

Step 1. Remove the Headlamp

Figure 1: Remove the lower trim piece by releasing the hook next to the fans, pivoting the piece out and unlatching the piece from the fender. Be careful not to break the little tab that latches to the fender sheet metal!

Four screws need to be removed, figures 2 & 3. While you're at it, unclip the cable harness and remove the air cleaner top cover, otherwise you will have very limited room.

Now you need to disconnect six (6) different electrical connectors. All have a little locking tab that needs to be pushed to release, as seen in figure 4. Next to the fender is the yellow turn signal connector, fig. 5., disconnect this first. Next are two connectors on the top edge of the headlamp (including the pilot bulb that had fallen out in my car), in fig. 6. Lastly, slide the headlamp out to disconnect the three connectors on the bottom edge, fig. 7. The gray connector is a major bitch, since the locking tab is very difficult to reach. At the end, the headlamp is free, as seen from the tail end in figure 8.

Step 2. Diagnose and repair the problem.

We had no clue to what the piece of plastic found inside was for, figure 9. However, the levelling mechanism requires the low and high beam reflectors to be mounted on a pivoting assembly, so let's examine the pivots.

First, let's take out the HID components to make room, figure 10. Unclip the wire going to the red igniter, then rotate it 30 degrees counterclockwise, which releases the connector. Lift the igniter carefully out. Rotate the black retaining ring counterclockwise until it releases and take out. Finally, with care extract the HID "bulb" out. Do NOT touch glass with bare fingers, fingerprints will bake in and cause premature dimming and failure. If contaminated, clean with microfiber cloth and isopropyl alcohol. The three pieces are in figure 11.

Looking from the rear end of the headlamp, the left pivot is attached to the horizontal aiming screw, and looks ok, figure 12. The right pivot would attach to the vertical aiming screw and the levelling servo, but there seems to be something wrong here! See figure 13 and 13a.

AHA! So that's where the mysterious piece came from!! Let's put it carefully in place with very long nosed pliers, figure 14. How to keep it in place? Dare not put glue in there for fear of sticking a moving piece and because of the high temp. Ok, lets WIRE it in place, using a convenient piece of copper (magneto) wire I had at hand, figure 15.

Step 3. Success!

Now we have to close the headlamp up, replace the dropped minibulb and slide everything in its receiver, figure 16.

Putting everything back in reverse order of extraction was fairly straightforward. The lower trim piece under the headlamp is somewhat ornery to fit, so don't tighten the four retaining screws till you get that in. Success is at hand, last figure.

Things to do:
  • A better repair could be done by going from the front. This is easy if you have a sedan, cause the lens unclips and removes easily.
  • If and when I bake my headlamps to install Angel Eyes, the piece will finally get glued and wired properly.
  • It was also a good time to polish the lens, but that will wait for the Angel Eyes as well.
  • In case of trouble on the other side, just remember it is a mirror setup. You have to take out the windshield washer bottle on that side.
  • While the headlamp is out, there are a number of other things you can do,which I will show in the next message (18 pic limit...)

jcourcoul 06-29-2009 06:44 PM

Other things to do...
4 Attachment(s)
While we're in place and with the headlamp out, here's a few other things you can do:
  1. Clean out the air box. Heck, change the air filter along the way!
  2. Fog lamp is readily accesible. Time to change or clean the bulb.
  3. The nefarious external temperature sensor is readily accesible now, way down below.
  4. Wanna put some new toots on the Bimmer? Horn's right at hand.
Hope this is useful to somebody.

Coconutpete 06-30-2009 07:50 AM

Nice Job!

It took me forever to figure out howt these headlights swivel & tilt... and I had the whole front of it off.......

Did you happen to notice in there which wires lead where for the up/down motors hehe?

jcourcoul 06-30-2009 08:35 AM


Originally Posted by Coconutpete (Post 4309583)
Did you happen to notice in there which wires lead where for the up/down motors hehe?

Thanks! No, I wanted to get the mechanicals in order and the car back in shape, cause a one-eyed Bimmer is something I did not want the local gang to see. I was hopin' you had figured out the wiring inside!! :rofl:

I'll have to check the WDS to determine what the OBC expects from its headlights. Is it open-ended, just dumping a voltage on the wires and hoping the servo gets the angle right? Or does it have an angle sensor in there as well, in a closed loop mode? We'll see...

BTW, if you or anybody needs to check how the car is wired, you use BMW's WDS or wiring diagram server. I found someone hosting this for free at:

P.S. Just checked the WDS, it is a closed-loop system: a servomotor to move it and a potentiometer to measure how far. Hence, four wires for the motor and three for the pot.

Coconutpete 06-30-2009 10:06 AM

Well I give you props for doing this from that little opening in the back, SERIOUS lack of space back there, it's a pain in the a$$.

I'm thinking that I'm going to wire this up without the potentiometer, just straight 12V on demand w/ a 2-way switch and a relay split to both sides. I'll put a cross on my garage wall for when I get home in case I crank them up too high while i am out in the woods (NO street lights within 8 miles of the in-laws).

I'm eyeballing a smashed up bixenon on ebay right now which i might pony up the dollars for just so I can rip it apart and wire up a test circuit w/ one of the servos from it.

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