You probably have the water distribution manifold on your coach -- on mine (a 2007 tour Master) there was an independent shutoff for just the ice maker in the residential refrigerator. On my coach, there is a small exterior access door that is at the bottom of the refrigerator where you might be able to access that 1/4 inch ice maker line.
Is your issue a leak on the line and you wish to repair it? Many times these ice maker lines get split due to freezing...it is not difficult to properly winterize this line, but is often overlooked.
It is quite a chore to fully remove the residential refrigerator on some coaches --on mine I simply moved it out part way to gain a bit more access from the exterior hatch. Because the refrigerator on my coach was mounted several inches above the floor level, I had to use a platform to do this. See my post #11 in this thread and the images it references...