Adaptive brightness sensor not working after replacing broken screen

While installing my replacement screen, I damaged the light sensor cable. With no instructions to follow, I swapped in the good cable from the broken screen. The connection seemed to be straightforward, but the sensor isn't functioning now.

If this cable is replaceable, clear instructions (and a replacement part option) would be helpful.

As an aside, reconnecting the screen cables is much more challenging than the instructions suggest (only describes as following the screen removal process in reverse, btw). In particular, a nice-to-have would be alternative guidance for left handed people, given the feasibility is directly impacted by the reconnection sequence.