Push the first stage button (the first position of the switch - the window moves till you release) and run the window to the top. Then push the button to the second position (the express button) and hold it a couple seconds. Run the window down with the first switch and hold again the second switch for a couple seconds. Now turn off the ignition. Turn the ignition back on and see if it works. If it don't try again.
Bosch Master, ASE Master, L1
33 years MB technician