Here's one for you. 2012 207 CC came in with roof not working and passenger rear window not going down. Car been to Peugeot who had changed BSI, butchered loom in driver's door and ruined the window motor. Also it has had a new comfort module (roof controller to me and you). No fault codes anywhere.

Basically, comfort module won't put rear window down until front window fully down. It knows this because motor module in front door tells it. The front motor module knows front window is down through current draw. Now before anyone spends a grand and a half guessing like this customer has, check the plugs in the A pillar. They are right inside the pillar and not easily seen. If water has got in and a bit of rot is starting then there maybe enough power for the window to work correctly but when the window gets to the bottom the slight resistance in the plug limits the current just enough for the motor module to think the window is still on its way down. The comfort module is still waiting to he told the front window is down and never tried to put the rear window down.

Peugeot diagnostic can do a full test on the system and it says there are no faults even though the front window never gets to the bottom as far as it knows while it tests the motor operations. Maybe its German, sort of thing you would expect on a Golf.