BMW M4 Mirror Heating & Auto-Dim Functions Dead

Hey there! I had a similar issue with my 2017 BMW M3 last winter. The heated mirrors and auto-dimming stopped working out of nowhere. Turned out the wiring harness connector at the mirror base was corroded and had some loose pins. Took it to my mechanic and they found that water had gotten into the connection point, causing the corrosion. It wasn't a major repair, just needed the connector cleaned, pins reseated, and they added some dielectric grease to prevent future issues. The whole thing took about an hour to fix. Since you're seeing error codes, it's likely an electrical connection issue rather than a complete mirror failure. These problems are fairly common in this generation of BMW mirrors. I'd suggest having a certified BMW technician check it out since they'll know exactly where to look and have the right diagnostic tools. Worth getting it fixed soon because moisture can spread to other connections if left unchecked. Hope this helps!

Hey, thanks so much for sharing your experience! This sounds exactly like what I'm dealing with. Such a relief to hear it wasn't anything major. Quick question, do you remember roughly how much you ended up paying for the repair? Also, has everything been working properly since they fixed it? Thanks again!

Hey again! Just wanted to update you, after getting it fixed, the heated mirrors have been working perfectly fine. No issues whatsoever since the repair, which was about three months ago now. The mechanic found exactly what I suspected, it was indeed a faulty cable connection that was causing all the trouble. The total bill came to 95 € for fixing the cable/plug connection. Pretty reasonable considering it sorted out both the heating and auto-dimming functions. To be honest, I was worried it might cost way more, so I was quite relieved! And yeah, everything's been working like a charm since then. The mirrors heat up quickly in cold weather, and the auto-dimming feature works just as it should. Really glad I didn't put off getting it fixed, especially since water damage could've made things worse. Let me know how you get on with yours! Always good to compare notes on these things.

Thanks for all the info! Just got back from my mechanic today and wanted to update you. You were spot on about the wiring issue! The connection was pretty corroded, and they found some moisture damage too. Ended up paying a bit more, around 120 € total, but they also did a full check of all the other mirror components while they were at it. Been testing everything for the past few hours and both the heating and auto-dimming are working perfectly now. Such a relief! Honestly, finding a new mechanic was the best decision. This guy really knew his stuff and explained everything clearly. He even showed me the corroded parts and what he did to fix them. Way better than my old mechanic who'd probably have charged double and taken days to sort it. Really appreciate your help pointing me in the right direction. Saved me loads of time and worry. Think I've found my new go-to mechanic too! Take care!