1995 BMW 525i rear side window issue

Suddenly both electrical rear side door windows will not move up to close. So far I removed both door panels to investigate issue. When window switch is pushed to close, I hear the motor, but no movement in regulator. I can only close window by pushing up with one hand on bottom window while other hand is on the switch. Is it common for both windows to not operate? Is the issue the regulator, motor or other electrical module. If module, where can I find the module that connects with windows?

Thanks