BMW Z4 Brake Light Warning Haunts Owner, Solutions Needed

I had the exact same issue with my 2015 BMW M4 last month. The brake light warning and error messages kept popping up, and it was driving me nuts. Turned out it wasn't just the brake light switch, there was a wiring harness problem that was causing intermittent failures in the entire brake light system. The technician found that moisture had gotten into the wiring connector, causing corrosion. Had to replace both the harness and the brake light switch. It was actually a good catch because the corroded wiring could have led to more serious electrical issues down the line. The fix wasn't too complex, but getting to the wiring harness was tricky. The whole repair took about 3 hours. Since then, no more warning lights or error messages. Just get it checked soon, electrical issues with brake lights aren't something you want to ignore.

Thanks for sharing your experience! Glad to hear you got it sorted. I'm going to head to the shop next week and have them check both the switch and the wiring harness. Do you remember roughly how much you ended up paying for the repair? Also, curious if you've had any other electrical gremlins pop up since getting it fixed?

Hey there! Just wanted to follow up about my M4 brake light situation. You'll be relieved to hear that my issue turned out to be way simpler than initially thought. After I posted about the wiring harness and all that, the mechanic actually found it was just a bad brake light switch, and get this, it wasn't even bad! I had accidentally knocked it loose while cleaning the pedal area. The mechanic just popped it back in place properly, and all those annoying warning lights disappeared instantly. Didn't cost me a single cent since it was just a mechanical error, pretty embarrassing actually but better than an expensive repair! Haven't had a single electrical issue since then, everything's working perfectly. The brake lights are functioning as they should, and the dashboard is finally clear of those pesky warning messages. Honestly, I feel a bit silly now about my first response where I thought it was this complicated wiring problem. Sometimes the simplest explanation is the right one!

Just got back from the mechanic, and you won't believe what happened! After all my worrying, it turned out to be such a simple fix. The mechanic found that one of the brake light bulbs was loose in its socket. He just removed it, cleaned the contacts, and secured it properly. The whole thing took less than 30 minutes, and they only charged me for a basic inspection. All those warning lights and error messages disappeared instantly. I feel kind of silly now for getting so worked up about it, but hey, better safe than sorry, right? No more electrical issues since then, everything's working perfectly. What a relief! Definitely learned my lesson about checking the basics first before assuming the worst. Thanks again for sharing your experience, it really helped me stay calm knowing others have dealt with similar situations.