Lumbar support not working?

[Radiatorkid]

Can someone tell me how the seat lumbar support system works on my 2000 Windstar? I can move the button foreward and hear sound coming from a black bag under the front of the seat. Nothing happens when I move the button to the rear. Even though I hear something in the bag, I feel no movement in the lumbar area of the seat. I'm getting tired of having to use a pillow!!