Rear seat ambient lighting issue

[volvof10]

Hi all, completely new to MB ownership, and picked up a 2009 CLS320 two weeks ago. I have turned off the ambient lighting using the steering wheel controls, and the front 'pod' has gone out. The rear one however still comes on when the headlights are switched on. There are two buttons on the rear 'pod' which appear to be for increasing or decreasing the brightness, but neither of these buttons make any difference to whichever light is switched on in the rear pod (main light, ambient light or reading lights). Can anyone tell me if I'm doing something wrong or if its a defect? Cheers.

 

[volvof10]

sorted - need to have the ambient lighting turned to at least '1' in order to get the rear switches to control. Turned the rear off completely using the switchesand then switched the ambient lighting back to '0' again