Two problems related to turn signal have been reported for the 2004 BMW 3 Series. The most recently reported issues are listed below.
Wire loosing coating on inside of adaptive headlights, causing shorts or broken wires where the headlights and or turn signals will fail to work. Wire is very brittle as this is also roughly 20 gauge wire. This can be an extreme hazard especially at night. This seems to be affecting BMW's 3/5/6/ series from at least 2004 to 2008 from my independent research. Many pictures and complaints on various BMW forums to document this problem. My problem occurred when I lost one headlight on my way home in the dark and an indicator came on to identify a fault in the headlight. Originally I though it was a bulb, changed bulb and it still did not work. Further investigation led to a broken wire inside of the headlight assembly. I fixed the broken wire and then noticed two more wires where the coating on the wire seem to have flaked off causing bare wire. I also fixed those wires and all was well. A day or two later, the indicator came on again pointing to the same headlight. This time the turn signal was out. I opened the access panel to check the wiring and now a forth wire has been severed, however I can not fix it as it is down pretty far inside the headlight and to repair would require removing the headlight and taking it apart. Apparently BMW used biodegradable wire for the headlights?? source of the headlight is believed to be hella. Supposedly BMW knows about the issue but unwilling to fix unless you purchase a $800-1500 new headlight. This is crazy for a car that is 10 years old and well maintained. This is a safety hazard as you will can loose a headlight in the dark and maybe both headlights going out, plus the fact of bare wires that can short and cause a fire.
The rear turn signals repeatedly fail. The wiring is melted. While this issue is addressed in NHTSA campaign id number: 11v438000, my car is not included in the recall. The recall should be expanded to include more cars. I called BMW customer service. They are indifferent to this issue and completely unconcerned about the safety issues created by their negligent manufacturing. Thanks,.