WARNING: This page is about a different car, the 2003 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Select Lever Cannot Be Shift Locked Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.
Fig 2: Select Lever Cannot Be Shift Locked Trouble Shooting Chart (1 Of 2)
Courtesy of SUBARU OF AMERICA, INC.
Fig 3: Select Lever Cannot Be Shift Locked Trouble Shooting Chart (2 Of 2)