The motor hardly breaks, more likely the window regulator. You could disassemble the windows and power up to confirm your suspicion. Do not disconnect the airbag unless you know how to reset airbag fault sig. There's bunch of articles here on this issue.
If you are brave enough do it yourself, save a bundle, and be a hero.
Some auto window shop might do cheaper than the dealers.
Good luck! I did fix this on my 5 yr old 3 series, it just takes initiative and through prep.