sunroof gone crazy..

[only_benz]

Hi everyone, my motorized sunroof lever (switch) has gone crazy. It is a 4-way swicth ('99 E320), has up/down/forward/back functions. Pressing it Up/down used to operate the sunroof up/down. Forward/back moved it forward/back. Now all of a sudden it has developed a mind of its own, and it cross-reacts. Example up will move it up, but down will not move it down. Now back will move it down and the same back will also move it back etc. etc. Sometimes forward would move it down and back would do nothing etc etc.

How can I re-adjust it to operate as it used to?