NHTSA Complaint #11595266 — 2023 GMC SIERRA 3500

We’ve had issues with the electrical system/brake lights when we hook any trailer (horse/boat/utility) to the truck. One issue is that the system shows unconnected and the trailer lights blink or do not work. We’ve brought this in to the dealer 3 times and they have yet to resolve the issue. The other issue of melted plastic on our rear sliding mirror. It just appeared one day, possible after using the rear defog button. We took it to the dealer and they also do not know what is the issue. We found several other blogs where owners have had the same issue. This is a newer vehicle, and we live in Southern California where the temperature is mild. It just appeared one day. We are concerned This is a safety issue with the electrical system melting the plastic and possibly causing a fire. Here is a link to a blog: [XXX] Lastly, this vehicle was advertised as having adaptive cruise and it does not have the capability (chip) to do so. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)