My response is for the people google searching for the answer to a no video feed/picture (black) and the truck still detects the camera.
I have a 2023 1500 LTZ 3.0. New trailer camera and had a blank screen. Ended up being because my data plan wasn't active. Activated that and the camera worked immediately. Also the calibration doesn't work unless angled down 30 degrees (I didn't have the instructions with me when I installed it), so don't point it level. After reactivating my data plan and a pointing the camera down 30 degrees the system works perfectly. Hope this helps someone.