WARNING: This page is about a different car, the 2009 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Horn - Wiring Diagram
Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Identifying Horn Connector Terminals (1 Of 3)
Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 3: Identifying Horn Connector Terminals (2 Of 3)
Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 4: Identifying Horn Connector Terminals (3 Of 3)