widow wiring query

[fonzooorooo]

Im looking at my mate's B4. Driver's leccy window has failed.

I have permanent 12V at the switch (red/white) , 2x earths (both brown) +12V when I press "up" on green/red for the driver and +12V on the other wire when I press "up" for the passenger. Obviously the blue/grey is convention for illumination.

The passenger window works faultlessly from the switch, but I can't tell how the switch "tells" the window what to do! The meter seems to read the same if the "down" button is pressed or if no buttons are pressed... What should I be seeing?

And how on earth do you get the sliding cover off the motor connector without obliterating it?!?!?