Hi Cuttyhunk.
My 98 V70 windows just started the exact same ratcheting sound but no movement you described. I've troubleshot what I could, and the clicking sound was coming from the switch cluster, specifically the driver's window switch. I made sure the wires were connected firmly and tapped the switch a few times. I tried it and the window worked. Of course, after the door panel was put back, the windows only worked once and now it is ratcheting again with no windows moving (but they are up). I also noted the power mirrors didn't move when the window switch just clicked, but they worked when the windows worked. Now that the window problem has recurred, the mirrors also don't move. So I'm thinking there's a connection somewhere between the windows and mirrors that might cause both problems. I don't have wiring diagrams for the car, but I suspect a loose ground or a bad component that shares wires with the mirrors and windows (if there is any). But I really suspect the driver's window switch as that is where the noise was coming from, so I'll start by changing that once I find a used part. I'll be away for about a week, so I won't have any updates for at least a week. But any suggestions from you or others would be helpful, especially if there is a component in the wiring that is upstream of both the windows and mirrors.
Youngster