2004 GMC Yukon Owner's Manual - Page 12

Reclining Seatbacks To adjust the front seatback, lift the manual lever located on the outboard side of the seat. Release the lever to lock the seatback where you want it. Lift the lever again without pushing on the seatback and the seatback will go to an upright position. If your vehicle has power seats with a power recliner, see Power Seats on page 1-4 for further information on how to operate the reclining seatback feature. But don't have a seatback reclined if your vehicle is moving. 1-6