Mercedes-Benz 2013 M Class - Manual (Page 97)

If the side window opens again slightly:
X Immediately pull the corresponding switch
on the door control panel until the side
window is completely closed (
Y page 92).
X Hold the switch for an additional second.
X If the corresponding side window remains
closed after the button has been released,
the side window has been reset correctly.
If this is not the case, repeat the steps
above again.
Side windows
95
Opening and closing
Z