W140 Rear Left Window problem

[pilot2000]

The other day I rolled down my window and it did not want o roll back up, from either the console switch or the panel switch. I managed to pull it up and hold it in place, both switches will take it down but will not roll it up. I can hear the motor click once you hit the switch to roll it up but nothing happens.

Any one with any ideas?

All other windows work fine

Thanks in advance