98' S500 rear seat cooling vents

[bourman]

I have a 1998 S500. The rear seat vents behind the center console continually
leak cold air. I can reduce the amount by closing the vent control, but cool air
still comes out. This car does not have the climate control option for the rear
seats.

With the heater on or off, I only get cold air out of the center rear vents.

Is there a duct somewhere under the center console that may have dropped
off or is this controlled by the vent system under the dash?

Thanks for your help.

BOBB