CHEVROLET 2010 HHR - Manual (Page 14)

Press the front or rear of the control to increase or
decrease lumbar support.
See Power Lumbar on page 2-6.
Second Row Seats
The seatbacks can be folded flat.
For detailed instructions for lowering the seatback(s),
see Split Folding Rear Seat on page 2-11.
Power Lumbar
1-8