2010 GL 450 rear entertainment
#4
On your remote there should be 4 buttons for source: Disc, TV, Aux 1, Aux 2. If you want both monitors to display Disc, you need to use the L/R button on the side and adjust each monitor to the source you want to watch.
#5
Sorry, didn't notice you have a 2010. prior instructions were for the remote from the 07/08. I looked at the remote from the 2010 and it seems you need to press the source then select disc. Your manual has all the details:
http://www.mbusa.com/vcm/MB/DigitalA...LK-CLS-R-G.pdf
http://www.mbusa.com/vcm/MB/DigitalA...LK-CLS-R-G.pdf