2023 Buick Envision Electrical System Problems

While driving in traffic, after changing lanes, the vehicle experienced a complete electrical shutdown without warning. The engine shut off, the dashboard went completely black, and hazard lights were not functional. There were no warning lights, messages, or audible alerts prior to the failure. The vehicle was in active traffic and, stopped without power steering or brake assist. After opening the hood, multiple wiring harnesses and a loose battery cable were visually observed. When wiring was physically moved, electrical power was immediately restored. Upon restart, the vehicle hesitated to start and then displayed messages instructing the driver to open and close the driver and passenger windows, indicating a full system reset due to power loss. We were able to return home safely. Parked the car, and obtained a rental. The vehicle had been serviced by the Buick dealership where the car was purchased, three days earlier. Two days after the incident, I was able to speak to someone at the dealership, who stated they may have bumped something. The vehicle was towed to the dealership, and assessed. The dealership later documented a loose battery cable and promised to replace a fatigued clip, but denied responsibility for the incident. I contacted the manufacturer, and was referred back to the dealership.The vehicle has only been inspected by the dealership. This incident created a serious safety risk, to our lives, as well as our fellow drivers' lives, as the vehicle lost all electrical power, including required safety lighting, while in traffic, without warning. The vehicle is available for inspection, upon request.

All the above are problems my car is experiencing

The contact owns a 2023 Buick Envision. The contact stated that upon purchasing the vehicle, the park assist sensor had not been installed in the vehicle. The contact was informed by the dealer that a letter would be sent once the sensor was available; however, the contact had not yet received the letter. Both the dealer and the manufacturer were notified of the issue and confirmed that the sensor was still unavailable. The vehicle was not repaired. The failure mileage was approximately 50.