I found a thread.
Is this correct?
From WIRE SIDE of small white plug
Mute wire (YEL/BLK) is in upper row, left pin
Move this wire to lower row, 4th pin from the left (empty pin between 2 black wires)
the pin directly below the mute wire does not work
Ground YEL/BLK & LT GRN and you're good to go