kaizersose

How many places in the brake light 'system' could there be an error? Am I destined to live with this error for the rest of the car's life? Help please!

My 2006 A3 3.2 has about 85000 miles on it and has been generally trouble free. About a month ago, a light popped up on the center driver display saying "LEFT BRAKE LIGHT" with a small symbol like a light bulb. I checked the brakes and everything was lighting up including running lights, brake lights and turn signal. The next time I started the car, there was no warning message and no codes were logged when I pulled them from the OBD port. However, after driving for 30 seconds or less, the warning came back on.

Attempted Fix 1: Changed the Battery
The battery was original to the car and being 10 years old, I thought maybe it wasn't producing as much power as it should. Plus, it's 10 years old and it should probably be changed even though I had no problems starting the car. I put in the brand new battery and while the car certainly starts a bit snappier, the warning light cam back on shortly thereafter.

Attempted Fix 2: Change all bulbs in left rear cluster
Bulbs are cheap and changing them is easy so I just changed every bulb in the cluster even though they seemed to work fine. I also unplugged the wire harness, blew out any dust and checked the bulb socket contacts (pristine, no corrosion or dirt). Warning light came back on shortly after driving a short distance.

At this point, I was sort of prepared to live with it, or at least know that it just might take a while to fix. Then a couple of days ago, the warning said "RIGHT BRAKE LIGHT" and part of me thought, "this is good, the left brake light error is gone." I should have known better.

Attempted Fix 3: Change all bulbs in right rear cluster
Lather, rinse repeat on the right side. No change and the LEFT BRAKE LIGHT error came back today as well.

Can I change out the voltage sensor for the error checking system? What else could it possibly be?

vetaldj

Have same thing happen to my 2006 A3 2.0T FSI. Had bunch of codes, put all new lights except 2. Still have LEFT BRAKE LIGHT warnings. Waiting for another 2 lamps... Hope it will be fixed.

Still new to the car so looking for solution as well.

Will post if I find something...

kaizersose

The error messages now come on immediately for both right and left brake lights and stay on the entire time the car is on. Everything still seems to work fine. I checked all of the fuses related to the lighting and braking system and they are healthy. Would love to figure out what this is without paying a hefty diagnostic fee.

vetaldj

Did you replace bulbs in both inner and outer clusters? I mean, all: 6 on outer and 4 in inner lights? That was helped me. Changing by cluster did not fixed my issues. It did help me to remove constant warning.
Now I have intermittent left brake light warning and it on and off while I'm driving. Looks like it is holder that is faulty in my case.

Also, do you have VAG-COM? You can reset those and see if they come back. If something is really off they will be back right away.

kaizersose

i replaced 6 total bulbs (3 right and 3 left). are there others?

fwiw, no codes are read by my generic OBDII reader. i dont have vag-com

vetaldj

Did you replaced 4 more for hatch mounted lights? Is your top hatch light is working?

What I learned that if at least one is out or on it's way out it will give you that code.

Generic scanner can't get those codes. They are unit specific and can be read with Vag Com cable/soft.

Check around, maybe someone near you have it and can do it for beer or two. If you would live in Orange County I could do it.

kaizersose

Damn! I totally missed the hatch mounted bulbs! Probably because the hatch was always open when i was working on the others. Sure enough, the bulb carrier and bulb in that housing had major corrosion at the connection. I can clean it off, but what's to stop it from happening again? Can I use the corrosion inhibitor that is used on the battery connection?

kaizersose

Finally got all the tools, parts and time to do the fix and it worked--no more errors.

The hardest part was getting the nut on and off of the threaded stud on the bulb carrier. You need a 10mm socket with a deep reach as the stud sticks out quite a ways when the nut is tightened down. The access and the angle are kind of funny as well which makes it hard to do with a ratchet/torque wrench. I ended up using the socket attached to a screwdriver until it started to get tight and then finishing it with the torque wrench at 2 NM.

Thanks vetaldj!

vetaldj

Glad I could help!

I also have BMW and I need to admit that owner's community is better there in terms of helping you with different aspect of the car then here...