Hi guys,
So recently I've been getting an intermittent 'right cornering light malfunction' on startup on my 2010 135i adaptive headlights, xenon. Weird thing is, when I checked the fault in the nav system, and clicked on the fault, the description would be 'left cornering light malfunction, please contact bmw etc.' Eventually the fault would appear more often and sometimes stay and sometimes clear itself while I drive. Even with the fault present, everything worked normally including the adaptive headlights.
I talked to a BMW technician and right away he knew the problem, he said I had to take out the headlight control unit, try cleaning the connections, and if that doesn't work then replace it ($380 online) AND that it needs to be programmed. It's part 14 on the realoem diagram, part no. 63117180050. Apparently moisture gets in there and fries the circuit board in that unit, but since mine was an intermittent fault I thought that cleaning might help and because of the right/left fault confusion, I just decided to clean both.
Disclaimer: I am not a certified mechanic. This DIY is solely an informative guide and I will not be held liable for any damage to your vehicle or harm done to yourself or anyone else while following these steps. I would not recommend following these steps if you cannot at a minimum SAFELY raise your vehicle with a jack and change a tire.
1. First things first, loosen lug nuts.
2. Raise vehicle with a jack. You can do one side at a time and use the forward side jack points, or raise the car from the front jack point.
3. Remove wheel and place under the car just in case. I would recommend using a jack stand of course. As always.. never get under a car that is solely supported by a jack.
4. Next we have to remove the wheel arch trim (fender liner or whatever else you would like to call that piece of plastic german engineering). Fortunately the arch trim is split in two so you only have to remove the front portion of it to get access to underneath the headlight. Part number 51118045961 is the driver's side one. It is held in place by:
1x 10mm nut in the wheel arch
5x 8mm screws also in the wheel arch
4x 8mm screws underneath where the trim meets the bumper
2x 8mm screws also underneath where the trim meets the engine skid plate/cover
Driver's side arch trim, if you follow the screws clockwise starting from the left you have the 5x 8mm screws then the 1x 10mm nut:
Once you have those off, you can remove 4 of the 8mm screws pictured below and pull out the black rubber insert:
The remaining 2x 8mm screws are behind that black rubber piece and pictured below:
5. With the forward wheel arch trim piece removed, you can easily see the headlight control unit (silver) directly mounted under and into the headlight, held in by 2x T20 torx screws. Remove those screws and slide the unit out.
Below is a picture of my passenger side headlight from the wheel arch, the control unit removed. You can see the oil cooler as well as the brake duct. Obviously the driver's side won't have the oil cooler but I pointed out the brake duct just to give you an idea relatively where the control unit is located:
6. Clean the connectors on both ends. I used alcohol and a q-tip for the control unit and a spray contact cleaner for the headlight connection.
7. The 'easy' part, putting everything back together
Just make sure when you place the forward wheel arch trim back in, that it slides above the aft wheel arch trim and above the engine skid plate/cover. Make sure all the holes line up, then and only then start putting the screws back in. Wheels back on. Lower car. Torque down lug nuts. Pray a little. Start the car and see what happens
After cleaning mine, the first time I started the car the fault came on as usual, but after about 2 minutes of driving went away and hasn't come back on for about two days. I will report back after a week to see if that really did solve the problem. Happy DIY'ing!