My driver's seat bolster stopped moving. I can hear the motor whining, and the the 4-way dial still operates the vertical lumbar support fine. It's the horizontal supports that move in/out from the sides of your torso that I'm talking about. Any suggestions on a fix? I've read gently that this could be some type of stripped plastic gearing assembly, or similar plastic guides like a window regulator. Has anyone replaced the offending components with success? Please help. Thanks!