Electrical, light, or ignition switch issue ???

james078

Member
OK, apologies for the long windedness up front, just want to get all the symptoms established for my issue... I have an 04' Z4 3.0i, 186K miles, bought it new, its 11 years old this month (Oct)...a couple weeks ago, my defective bulb indicator began to come on intermittently and go off, so I was expecting I had a bulb somewhere going bad.

I checked all the lights when it was on, did not find anything...last week, when it was on, my left turn signal began flashing rapidly, so I thought maybe I my bad bulb had exposed itself, but all the bulbs showed ok, and by the end of the day, it was flashing normal again and the indicator went back off...yesterday, when I got ready to leave work, I pressed the remote to open the door and trunk, and my exterior parking lamps all came on. I do not have an alarm system, and these had never come on before, so that was strange. When I opened the door, the chime sounded as if I had left my key in the ignition, but my key was in my hand. It bleeped about 7-8 times then stopped...I started my car, no problems starting, but my left turn signal is flashing, and I cannot turn it off... the turn signal switch has no bearing on operating the signal lights at all...also, the headlamp switch, which I keep on automatic all the time, also has no impact on the lights...the fog light switch also does nothing, as does the dimmer for the dash lights.

After a 40 minute ride home with my left signal flashing, I shut the car off and the parking lamps remain illuminated, and will not turn off...I decided to disconnect the battery, waited 10 minutes and reconnected...the turn signal is now off, but all the exterior lights are not operational (headlamps, fog lamps, turn signals), and the chime sounds as described before without the key when I open the door.

I checked al the applicable fuses in the fuse block, did not find any faulty fuses...I disconnected the battery again, checked its voltage with a multi-meter, it shows 12.7 volts...from what I've read so far in other posts/blogs, it sounds like either a ignition switch issue not allowing power to the light systems, or the headlamp switch itself which I understand has a built-in light control module...the ignition switch has never been replaced, looks to be fairly inexpensive and easy to replace, so I thought I would start there...if its the headlamp switch/module, it is more pricey and I understand it has to be programmed at the dealership?

Anyone with thoughts or ideas greatly appreciated...
 
Update - I replaced the ignition switch this AM, but it did not fix my issue :-( Going to do some more research, but appears my headlamp/light control module is at fault...any other thoughts or ideas appreciated...
 
Update - The alternator and regulator both checked out with no issues, and since I had no light controls per my first post, couldn't really do much else... I found a used LCM on eBay, compared part numbers since there have been multiple superseding part numbers...I found one that was identical part number as mine and appears have been in the same lot grouping from Lear, the manufacturer...I ordered it, got it today, and just installed...vola,I have functioning lights again!!! All is well!!!
 
Presume you have programmed the LCM to the car to prevent the mileage tamper dot from appearing.
 
I have not done that yet...I've ordered the suite of diagnostic/programming tools to do this with, figured I needed it anyways as I've got some other small issues needing attention (SRS light reset)...I took the seats out to clean my carpet, unfortunately I turned the key on and it triggered the SRS fault...
 
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