Section 131 (Power Seat System): Lumbar: Operation
WARNING: This page is about a different car, the 2006 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
The lumbar adjuster lever, located on the inboard side of each front seat attaches to a cable located inside the seat back. This cable/lever operates the lumbar adjuster mechanism. When the lumbar adjuster lever is moved up/down the attached cable is extended or retracted. The action of this cable compresses or relaxes a grid of flexible slats, located in the seat back. The more this grid is compressed, the more the slats bow outward against the center of the seat back padding, providing additional lumbar support.