NHTSA Complaint #11673998 — 2023 GMC TERRAIN

My son was making a left onto a freeway on ramp after traffic cleared and the steering wheel completely locked up resulting in him going over the curb and rolling completely over in a steep ditch. This occurred at a low speed (no more than 25mph), confirmed by the Life369 app. My son's description was that it felt like the wheels were against a wall and the wheel wouldn't turn even though he was using both hands in an attempt to turn. My son said there was no warning lights or any other indication that he noticed, other than the complete locking up of the steering. The resulting rollover into the ditch has totaled the vehicle so it was not inspected by any collision shop. I attempted to check the steering in the tow yard but the vehicle had no power.