Do you have the "Dynamic Seats" option? Go around a corner and the seat back bolster inflates to keep the driver stable, basically? If so, the "bladders" tend to deteriorate over time. Fancy phrasing for the gd things leak. Indeed, there is a pump that inflates all associated. A chip shuts it down, if the pump is essentially blowing into a busted balloon. Typically, you can clear the fault codes and then all is well.....for a little while. The chips catch up and there ya sit. If all you want is to get the rear head rests down, clear the faults and be ready to hit knock down on your center console. Then, until you get the bladders fixed (bring money), don't raise the headrests. That was my experience years ago. May be wrong, but offering an experience. Good luck.