If the motor works from the passenger side switch then it works.  It is the
driver's side switch.  It sounds to me like loose connections on the back of
the switch.  I was looking at the back of my switch today and was surprised to
find that the connections were soldered!  In aircraft electrical systems we
rarely solder connections in areas subject to vibration or shock (doors
slamming) since they tend to brake under those situations.  If you can get
your switch out of the door check the connections on the passenger side window
switch for security of attachment and corrosion.  I bet one of your wires is
loose or broken.  Or one of the terminals is.
Ken Wilford
John 3:16