Buick 2009 Lucerne - Manual (Page 10)

Power Lumbar
On vehicles with power lumbar, the control is located on
the outboard side of the front seats.
For vehicles with a two-way lumbar control, press the
control top or bottom to increase or decrease support in
the lower seatback.
On vehicles with a four-way lumbar control, press the
control forward or rearward to increase or decrease
support in the lower seatback. Press the top or bottom
of the control to raise or lower the support in the
seatback.
The lumbar support may need to be re-adjusted when
changing the seating position.
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