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Diagnostic Procedure

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SYMPTOM: Blower motor operation is malfunctioning under Starting Fan Speed Control.

Fig 1: Blower Motor Operation Diagnostic Procedure
G02162427Courtesy of NISSAN MOTOR CO., U.S.A.
  1. CHECK POWER SUPPLY FOR FAN CONTROL AMP. 
    Fig 2: Checking Fan Control Amp Power Supply (1 Of 2)
    G02162428Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 3: Checking Fan Control Amp Power Supply (2 Of 2)
    G02162429Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    1. Yes: GO TO 2.
    2. No: GO TO  8.
  2. CHECK BODY GROUND CIRCUIT FOR FAN CONTROL AMP. 
    Fig 4: Checking Fan Control Amp Body Ground Circuit (1 Of 2)
    G02162430Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 5: Checking Fan Control Amp Body Ground Circuit (2 Of 2)
    G02162431Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    1. Yes: Reconnect fan control amp. harness connector and GO TO 3.
    2. No: Repair harness or connector.
  3. CHECK VOLTAGE FOR FAN CONTROL AMP. 

    Set up Self-diagnosis STEP 4.

    Fig 6: Checking Fan Control Amp Voltage (1 Of 2)
    G02162432Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 7: Checking Fan Control Amp Voltage (2 Of 2)
    G02162433Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 4.
    2. NG:
      1. If the voltage is less than 2.5V, replace fan control amp.
      2. If the voltage is more than 3.0V, GO TO 4.
      3. Go to "FUNCTION CONFIRMATION PROCEDURE", refer to "SELF-DIAGNOSIS " and perform self-diagnosis STEP 4.

      Confirm that blower motor operation is normal.

  4. CHECK FAN CONTROL AMP. 

    Refer to "FAN CONTROL AMP. "

    OK or NG 

    1. OK: GO TO 5.
    2. NG:
      1. Replace fan control amp.
      2. Go to "FUNCTION CONFIRMATION PROCEDURE", refer to "SELF-DIAGNOSIS " and perform self-diagnosis STEP 4.

        Confirm that blower motor operation is normal.

  5. CHECK FAN CONTROL AMP. CIRCUIT BETWEEN FAN CONTROL AMP. AND AUTO AMP. (LCU) 
    1. Disconnect auto amp. (LCU) and fan control amp. harness connector.
      Fig 8: Checking Fan Control AMP. Circuit (1 Of 2)
      G02162434Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 9: Checking Fan Control AMP. Circuit (2 Of 2)
      G02162435Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should exist. 

    If OK, check harness for short.

    OK or NG 

    1. OK: GO TO 6.
    2. NG: Repair harness or connector.
  6. CHECK FAN FEEDBACK CIRCUIT 

    Reconnect auto amp. (LCU) harness connector.

    Fig 10: Checking Fan Feedback Circuit (1 Of 2)
    G02162436Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 11: Checking Fan Feedback Circuit (2 Of 2)
    G02162437Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    1. Yes: GO TO 7.
    2. No:
      • If OK, check for open circuit in wiring harness. Repair or replace as necessary.
      • If NG, replace fuse and check wiring harness for short circuit. Repair or replace as necessary.
  7. CHECK POWER SUPPLY FOR AUTO AMP. 
    Fig 12: Checking Auto Amp Power Supply (1 Of 2)
    G02162438Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 13: Checking Auto Amp Power Supply (2 Of 2)
    G02162439Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    1. Yes:
      1. Replace auto amp.
      2. Go to "FUNCTION CONFIRMATION PROCEDURE", refer to "SELF-DIAGNOSIS  " and perform self-diagnosis STEP 4.

        Confirm that blower motor operation is normal.

    2. No: GO TO  10.
  8. CHECK POWER SUPPLY FOR BLOWER MOTOR 

    Disconnect blower motor harness connector.

    Fig 14: Checking Blower Motor Power Supply (1 Of 2)
    G02162440Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 15: Checking Blower Motor Power Supply (2 Of 2)
    G02162441Courtesy of NISSAN MOTOR CO., U.S.A.

    Yes or No 

    1. Yes: GO TO 9.
    2. No: Check power supply circuit and 15A fuses [Nos. 10 and 11, located in the fuse block (J/B)].
      • Check blower motor relay.
      • If OK, check for open circuit in wiring harness. Repair or replace as necessary.
      • If NG, replace fuse and check wiring harness for short circuit. Repair or replace as necessary.
  9. CHECK CIRCUIT CONTINUITY BETWEEN BLOWER MOTOR AND FAN CONTROL AMP. 

    Disconnect blower motor connector and auto amp. (LCU) connector

    Fig 16: Checking Circuit Continuity Between Blower Motor And Fan Control Amp (1 Of 2)
    G02162442Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 17: Checking Circuit Continuity Between Blower Motor And Fan Control Amp (2 Of 2)
    G02162443Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: Check blower motor. Refer to "BLOWER MOTOR "
      1. If NG, replace blower motor.
      2. Go to "FUNCTION CONFIRMATION PROCEDURE", refer to "SELF-DIAGNOSIS  " and perform self-diagnosis STEP 4.

        Confirm that blower motor operation is normal.

    2. NG: Repair harness or connector.
  10. CHECK BLOWER MOTOR CIRCUIT BETWEEN BLOWER MOTOR AND AUTO AMP. (LCU) 
    Fig 18: Checking Blower Motor Circuit Between Blower Motor And Auto Amp. (LCU) (1 Of 2)
    G02162444Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 19: Checking Blower Motor Circuit Between Blower Motor And Auto Amp. (LCU) (2 Of 2)
    G02162445Courtesy of NISSAN MOTOR CO., U.S.A.

    Continuity should exist. 

    If OK, check harness for short.

    OK or NG 

    1. OK: INSPECTION END
    2. NG: Repair harness or connector.
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