[GSB]

My sunroof also began randomly opening and closing itself, and nothing is more annoying than having a wide-open sunroof that cannot be kept closed when it's pouring with rain. My car and its occupants quickly became drenched inside. This problem also randomly occurs after locking the car and walking away.

My car is a 2008 E92 335i, which has an SOS button and a passenger airbag indicator on either side of the sunroof button.

In time, things became WAY worse. Suddenly, the audio system blew up with a non-stop crescendo of extremely loud (and alarming) pops, bangs and crackles from the speakers, whether the radio head-unit was turned on or not. An hour later, the audio system was dead... The head unit was still powered up and responsive to any kind of user-input, but there was no sound at all. The amp in the trunk was perfectly dry, properly connected, and powered up. A couple of days later, the SOS-button LED began flickering wildly, and the display on the radio head-unit indicated that it was contacting BMW, but still no sound. Days later, the passenger airbag warning LED started flickering wildly as well. Finally, the display on the radio head-unit began flickering and going out too.

I removed the Roof Function Center (FZD) console and inspected the wiring, connectors, switches and the circuit board. Nothing stood out as being defective, until I discovered a SUPER-thin haze all over the board and every component of the roof console. It was a faint, smokey-gray coating that was only visible on the white plastic parts. It was easily wiped off with a finger. It was road pollution, very slightly oily, mostly smokey. And most significantly, this coating was all over the exposed contacts of every single switch. This coating is hygroscopic, meaning that it draws and retains moisture from the air, which then alters the resistance across the switch contacts, ESPECIALLY in damp weather. Note that every push-button switch presses a conductive-rubber foot across a pair of exposed contacts on the circuit board, causing a resistance drop across those contacts. Electronic circuits on the board are designed to sense the "open" and "closed" resistances across each pair of contacts. A fine coating of road pollution is sufficient to alter those resistances significantly, causing false-triggers and shorts at the output of the sensing-circuits.

I used 92% rubbing alcohol on a microfiber cloth to carefully clean the entire circuit board, paying special attention to every switch contact, every rubber foot on the push-buttons, as well as the metal sliding contacts on the sunroof switch. The red markups on the photo show the locations of the switch contact pairs on the board. Remove, clean, and replace the silicone/rubber mats, which house a small rubber foot for each contact pair. Gently wipe this rubber with alcohol until clean, but do not soak.

ALL symptoms were instantly cured, and every electrical function has remained perfectly reliable for several rainy months now. The audio system works perfectly, the sunroof works perfectly, the SOS button and the passenger airbag warning works perfectly. And NO software "sunroof normalization" was required. Imperceptible contamination of this circuit board obviously has far-reaching effects throughout the car.