It seems that the hinged third row windows are no longer in the GL.
The physical window itself is still hinged, but the switch to open them is not installed (!)
It's standard in the 2014 GL63, but "decontented" from the GL550 and all those "lesser" GL's ...
The functionality (opening with the sunroof to vent the car on a warm day) is still there in the owner's manual, but somehow just deleted from the car assembly.

Has anyone else figured out how to install the switch or turn on the computer function to open the windows from the key fob?

 

it only comes in the 14's with the pano roof package.

it was standard on the 13's , as it was with the previous X164 GL's.

 

Yup….

 

From what MBUSA communicated to the dealership general manager, during 2013 model year, the hinged opening third row window was decontented, so not all 2013's have that functionality.

For 2014 x166 the opening third row window is available only in the AMG GL63. Perhaps this ignores the panoramic roof option.

In any case, my car was built with low range transfer case off-road option which does not appear to be available to build. If it's even possible to build a car with the off-road options, I think the panoramic roof is useless to me. I've had it in other SUVs and preferred to have the money in my pocket and the space over my head.