With CONSULT-II

See "DOOR LK SW-LK and UN" in DATA MONITOR mode with CONSULT-II.

• When door lock and unlock switch is turned to lock:
  1. DOOK LK SW-LK: ON 
• When lock and unlock switch is turned to unlock:
  1. DOOR LK SW-UN: ON 

Fig 1: Checking Door Lock And Unlock Switch With CONSULT-II

Courtesy of NISSAN MOTOR CO., U.S.A.