WARNING: This page is about a different car, the 2003 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
Check continuity between terminals 3 and 4.
Fig 1: Transfer Shift Relay (High And Low) Continuity Specifications
Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Checking Continuity Between Transfer Shift Relay (High And Low) Terminals