In the Chrysler it's done using an aftermarket gizmo called a Tazer. Turning the AWD on/off is an option within the body computer but there's no factory button. The Tazer accesses that menu and allows it to be programmed to one of the adaptive cruise control buttons on the steering wheel. The closest video I found is this but he doesn't show the steering wheel programing.

I largely accomplish the same thing with the use of the Tazer and the traction control options. As mentioned I can turn the AWD off with the Tazer. The traction control also has what Chrysler calls a "partial off" setting. This setting removes the stability controls ability to remove power and increases the yaw threshold before the stability control system intervenes. This is accessed using an on dash button.

Maybe I'll make a vid.