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Home >> Nissan-Datsun >> 2004 >> Altima S, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 886 (Automatic Air Conditioner) >> Trouble Diagnosis >> Power Supply and Ground Circuit for Front Air Control and Unified Meter and A/C Amp. >> Diagnostic Procedure For A/C System

Diagnostic Procedure For A/C System

WARNING: This page is about a different car, the 2007 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM: A/C system does not come on.

Fig 1: A/C System Diagnostic Circuit (1 Of 2)
G04917549Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: A/C System Diagnostic Circuit (2 Of 2)
G04917550Courtesy of NISSAN MOTOR CO., U.S.A.
  1. CHECK FRONT AIR CONTROL 

    Perform front air control self-diagnosis. Refer to "FRONT AIR CONTROL SELF - DIAGNOSIS ".

    OK or NG 

    OK: GO TO  4.

    NG: GO TO  2.

  2. CHECK POWER SUPPLY CIRCUIT FOR FRONT AIR CONTROL  .
    1. Turn ignition switch OFF.
    2. Disconnect front air control connector.
    3. Turn ignition switch ON.
    4. Check voltage between unified meter and A/C amp. harness connector M49 terminal 1 and ground.
      POWER SUPPLY CIRCUIT FOR FRONT AIR CONTROL

      Terminals Ignition switch position
      (+) (-) OFF ACC ON
      Front air control Terminal No.
      M201 1 Ground Approx. 0V Approx. 0V Battery voltage
      Fig 3: Checking Voltage Between Unified Meter And A/C Amp. Harness Connector M49 Terminal 1 And Ground
      G04917551Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO  3.

    NG: Check harness for open circuit. Repair harness as necessary.

  3. CHECK GROUND CIRCUIT FOR FRONT AIR CONTROL 
    1. Turn ignition switch OFF.
    2. Check continuity between front air control harness connector M201 terminal 2 and ground.

      2 - Ground: Continuity should exist  .

    Fig 4: Checking Continuity Between Front Air Control Harness Connector M201 Terminal 2 And Ground
    G04917552Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: Replace front air control. Refer to "CENTER STACK ASSEMBLY ".

    NG: Repair harness or connector.

  4. CHECK POWER SUPPLY CIRCUIT FOR UNIFIED METER AND A/C AMP  .
    1. Turn ignition switch OFF.
    2. Disconnect unified meter and A/C amp. connector.
    3. Check voltage between unified meter and A/C amp. harness connector M50 terminals 21, 22 and 35, unified meter and A/C amp. harness connector M89 terminal 46 and ground.
      POWER SUPPLY CIRCUIT FOR UNIFIED METER AND A/C AMP

      Terminals Ignition switch position
      (+) (-) OFF ACC ON
      Unified meter and A/C amp. connector Terminal No.
      M50 21 Ground Battery voltage Battery voltage Battery voltage
      M50 22 Approx. 0V Approx. 0V Battery voltage
      M50 35 Approx. 0V Battery voltage Battery voltage
      M89 46 Approx. 0V Approx. 0V Battery voltage
      Fig 5: Checking Power Supply Circuit For Unified Meter And A/C Amp
      G04917553Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO  5.

    NG: Check fuses [Nos. 6, 12 and 19 (10A) and 10 (15A), located in the fuse block (J/B)]. Refer to "FUSE BLOCK-JUNCTION BOX (J/B) ".

    • If fuses are OK, check harness for open circuit. Repair or replace as necessary.
    • If fuses are NG, replace fuse and check harness for short circuit. Repair or replace as necessary.
  5. CHECK GROUND CIRCUIT FOR UNIFIED METER AND A/C AMP  .
    1. Turn ignition switch OFF.
    2. Check continuity between unified meter and A/C amp. harness connector M50 terminals 29, 30 and ground.

      29, 30 - Ground: Continuity should exist  .

    Fig 6: Checking Continuity Between Unified Meter And A/C Amp. Harness Connector M50 Terminal 29, 30 And Ground
    G04917554Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: Check multiplex communication circuit. Refer to "MULTIPLEX COMMUNICATION CIRCUIT ".

    NG: Repair harness or connector.

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