Just today my passenger door power lock failed. If I press the door lock from either the driver or passenger door, the driver door lock will move, yet the passenger door lock does not move. When I press the power lock button (either one), I hear a click coming from under the glovebox in front of the passenger seat, but I cannot identify exactly where it comes from. I do not recall if I heard that before this problem. I can, of course, manually lock the door.

Does anyone know why this is happening?