rear seat vent 95S420 (w140)

[tower]

I'm attempting to stop the cool air from constantly blowing into the rear seat area. It appears that the centre console (behind the arm rest for the cell phone) control does not close the flapper and the cold air (in winter) is free to blow in on the occupants. How do you get to the flapper.

I can pull the grill/deflector free of the duct, but I cannot see anyway to release the cable from the assembly. Is there an easier way?

Regards to all.
Ron