Yoo've insulted the fine German engineering on this car, which is smart enought to know that even though you may want to, you really shouldn't lower the windows when it's cold outside:-) I assume you've only hit the switches on the center console. Have you tried, when it fails, to use the switches on the rear doors? If the rear door switches work and none of the center console switches do, you've isolated it to the console switch. If no switches work at all, it would point to the relay module located in the rear power distribution box, which is located beneath the left rear seat cushion. There are a several relays in the box; this one is a longest module, and it's on on the top side. Hope this helps, others may know more; this is just what I've gleaned from the manual. I haven't had the problem. On the other hand, the previous owner accepted the zen and was happy; perhaps you can learn from this, pilgrim.