Communication Line Check (Between NAVI Switch and NAVI Control Unit)

WARNING: This page is about a different car, the 2004 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.

CHECK POWER SUPPLY AND GROUND CIRCUIT (NAVI SWITCH)
1. Check power supply and ground circuit. Refer to POWER SUPPLY AND GROUND CIRCUIT CHECK FOR DISPLAY UNIT AND NAVI SWITCH .
OK or NG
1. OK: GO TO 2.
2. NG: Power supply and ground circuit check.
CHECK HARNESS
1. Turn ignition switch OFF.
2. Disconnect NAVI switch connector and NAVI control unit connector.
3. Check continuity between NAVI switch harness connector M37 terminal 5 (G) and NAVI control unit connector M58 terminal 33(G).
  Continuity should exist.
4. Check continuity between NAVI switch harness connector M37 terminal 5 (G) and ground.
  Continuity should not exist.
  
  Fig 1: Checking Continuity Between NAVI Switch Harness Connector M37 Terminal 5 (G) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 3.
2. NG: Repair harness or connector.
COMMUNICATION SIGNAL CHECK
1. Connect NAVI switch connector.
2. Turn ignition switch ON.
3. Check voltage between NAVI switch harness connector M37 terminal 5 (G) and ground.
  5 (G) - Ground: Approx 5V
OK or NG
1. OK: Replace NAVI control unit.
2. NG: Replace NAVI switch.
  
  Fig 2: Checking Voltage Between NAVI Switch Harness Connector M37 Terminal 5 (G) And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.