I recently purchased a 1990 Bentley Turbo R, the front passenger door window lift has a problem. The motor was non op I managed to find another and fitted it, but it did not move the window. If I disconnect the chain from the lower window frame the motor will send the chain up and down effortlessly, however when I connect it back to the frame the motor will not move the window in either direction. I can manually move the window up and down with the chain attached. I tried moving the front track thinking it may have been out of alignment, but no change. Any ideas anyone?