Dear colleagues,
on my Xantia Mk2 the front passenger window regulator is stuck in the lowest position. I am gathering some hints before I start the operation this afternoon

How to disengage the glass from the lifter, when it is jammed in the lowest position? I suspect the cables are wound around something and the motor does not move. When the window button is pressed, the cabin lights get slightly dimmed, so I think, the motor is energised but cannot move.
Thanks for any tips!
Karel