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Home >> Infiniti >> 2004 >> G35 x >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> 2004.5 - Automatic Air Conditioner - Sedan >> Trouble Diagnosis >> LAN System Circuit >> Diagnostic Procedure For LAN Circuit

Diagnostic Procedure For LAN Circuit

  1. CHECK POWER SUPPLY FOR DISPLAY AND A/C AUTO AMP. 
    1. Turn ignition switch ON.
    2. Check voltage between display and A/C auto amp. harness connector M32 terminal 21 (Y/R) and ground.

      21 - Ground: Battery voltage 

      Fig 1: Checking Power Supply Display And A/C Auto Amp
      G03327663Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 2.
    2. NG: Replace display and A/C auto amp.
  2. CHECK SIGNAL FOR DISPLAY AND A/C AUTO AMP. 

    Confirm A/C LAN signal between display and A/C auto amp. harness connector M31 terminal 5 (G/B) and ground using an oscilloscope.

    Fig 2: Oscilloscope Signal Chart
    G03327664Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 3: Checking Signal Display And A/C Auto Amp
    G03327665Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 3.
    2. NG: Replace display and A/C auto amp.
  3. CHECK POWER SUPPLY FOR MOTOR 

    Check voltage between mode door motor harness connector M252 terminal 1 (Y/R), passenger side air mix door motor harness connector M253 terminal 1 (Y/R), driver side air mix door motor harness connector M17 terminal 1 (Y/R), intake door motor harness connector M67 terminal 1 (Y/R) and ground.

    1 - Ground: Battery voltage 

    Fig 4: Checking Power Supply For Motor
    G03327666Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 4.
    2. NG: Replace harness or connector.
  4. CHECK SIGNAL FOR MOTOR 

    Confirm A/C LAN signal between mode door motor harness connector M252 terminal 3 (G/B), passenger side air mix door motor harness connector M253 terminal 3 (G/B), driver side air mix door motor harness connector M17 terminal 3 (G/B), intake door motor harness connector M67 terminal 3 (G/B) and ground using an oscilloscope.

    Fig 5: Oscilloscope Signal Chart
    G03327667Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 6: Checking Signal For Motor
    G03327668Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 5.
    2. NG: Replace harness or connector.
  5. CHECK MOTOR GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect door motor connector.
    3. Check continuity between mode door motor harness connector M252 terminal 2 (B), passenger side air mix door motor harness connector M253 terminal 2 (B), driver side air mix door motor harness connector M17 terminal 2 (B), intake door motor harness connector M67 terminal 2 (B) and ground.

      2 - Ground: Continuity should exist. 

      Fig 7: Checking Motor Ground Circuit
      G03327669Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 6.
    2. NG: Replace harness or connector.
  6. CHECK MOTOR OPERATION 
    1. Turn ignition switch OFF.
    2. Disconnect each door motor connector.
    3. Reconnect each door motor connector.
    4. Turn ignition switch ON.
    5. Confirm each door motor operation.

    OK or NG 

    1. OK: (Return to operate normally.)
      • Poor contact in motor connector.
    2. NG: (Does not operate normally.)
      • GO TO 7.
  7. CHECK MODE DOOR MOTOR OPERATION 
    1. Turn ignition switch OFF.
    2. Disconnect mode door motor and air mix door motor (driver side, passenger side) connector.
    3. Reconnect mode door motor connector.
    4. Turn ignition switch ON.
    5. Confirm the mode door motor operation.

    OK or NG 

    1. OK: (Mode door motor operates normally.)
      • GO TO 8.
    2. NG: (Mode door motor does not operate normally.)
      • Repair mode door motor.
  8. CHECK AIR MIX DOOR MOTOR OPERATION 
    1. Turn ignition switch OFF.
    2. Disconnect mode door motor connector.
    3. Reconnect air mix door motor connector (driver side, passenger side).
    4. Turn ignition switch ON.
    5. Confirm the air mix door motor operation.

    OK or NG 

    1. OK: (Air mix door motor operates normally.)
      • GO TO 9.
    2. NG: (Air mix door motor does not operate normally.)
      • GO TO  10.
  9. CHECK INTAKE DOOR MOTOR OPERATION 
    1. Turn ignition switch OFF.
    2. Disconnect air mix door motor connector (driver side, passenger side).
    3. Reconnect intake door motor connector.
    4. Turn ignition switch ON.
    5. Confirm the intake door motor operation.

    OK or NG 

    1. OK: (Intake door motor operates normally.)
      • Repair unified meter and A/C amp.
    2. NG: (Intake door motor does not operate normally.)
      • Repair intake door motor.
  10. CHECK AIR MIX DOOR MOTOR OPERATION 
    1. Turn ignition switch OFF.
    2. Disconnect air mix door motor (driver side) connector.
    3. Turn ignition switch ON.
    4. Confirm the air mix door motor (passenger side) operation.

    OK or NG 

    1. OK: (Air mix door motor operates normally.)
      • Repair driver side air mix door motor.
    2. NG: (Air mix door motor does not operate normally.)
      • Repair passenger side air mix door motor.
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