Please skip to subject #3 in the video:
remove the Communication Cable from the Primary Control Unit by turning the cable nut counterclockwise and gently pulling it out.
Repeat this process for the other side of the communication cable which is connected to the Secondary Control Unit.
Connect it back tightly- Insert the female side to the Primary Control Unit and turn
the nut clockwise to tighten it. Insert the male side to the Secondary Control Unit and turn the nut clockwise to tighten it.