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Diagnostic Procedure For Blower Motor

WARNING: This page is about a different car, the 2005 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM: Blower motor operation is malfunctioning under starting fan speed control.

Fig 1: Blower Motor Circuit Diagram
G02476914Courtesy of NISSAN MOTOR CO., U.S.A.
  1. CHECK FUSES 

    Check 20A fuses [No. 28 and 30 (Located in the fuse and fusible link box)]. For fuse layout. Refer to "FUSE AND FUSIBLE LINK BOX ".

    Fuses are good. 

    OK or NG

    • OK: GO TO 2.
    • NG: GO TO  10.
  2. CHECK FRONT BLOWER MOTOR POWER SUPPLY CIRCUIT 
    1. Disconnect front blower motor connector.
    2. Press the mode switch to select any mode except off.
    3. Set fan switch to high.
    4. Check voltage between front blower motor harness connector M62 terminal + (W/L) and ground.
      Fig 2: Checking Voltage Between Front Blower Motor Harness Connector M62 Terminal + & Ground
      G04200546Courtesy of NISSAN MOTOR CO., U.S.A.
      • Battery voltage should exist. 

    OK or NG

    • OK: GO TO  12.
    • NG: GO TO 3.
  3. CHECK FRONT BLOWER MOTOR RELAY (SWITCH SIDE) POWER SUPPLY CIRCUIT 
    1. Disconnect front blower motor relay connector.
    2. Check voltage between front blower motor relay harness connector H-2 terminals 3 (L) and 6 (L/W) and ground.
      Fig 3: Connecting Jumper Wire Between Front Blower Motor Relay Connector H2 Terminal 3, 6 & Ground
      G02476916Courtesy of NISSAN MOTOR CO., U.S.A.
      • Battery voltage should exist. 

    OK or NG

    • OK: GO TO 4.
    • NG: Repair harness or connector.
  4. CHECK FRONT BLOWER MOTOR RELAY 

    Refer to "FRONT BLOWER MOTOR RELAY ".

    OK or NG

    • OK: GO TO 5.
    • NG: Replace front blower motor relay.
  5. CHECK FRONT BLOWER MOTOR RELAY (SWITCH SIDE) CIRCUIT FOR OPEN 

    Check continuity between front blower motor relay harness connector H-2 terminals 5 (W/L) and 7 (W/L) and front blower motor harness connector M62 terminal + (W/L).

    Fig 4: Checking Voltage Between Front Blower Motor Relay Harness Connector H2 Terminals 5, 7 & Front Blower Motor Harness Connector M62 Terminal +
    G02476917Courtesy of NISSAN MOTOR CO., U.S.A.
    • Continuity should exist. 

    OK or NG

    • OK: GO TO 6.
    • NG: Repair harness or connector.
  6. CHECK VARIABLE BLOWER CONTROL POWER SUPPLY CIRCUIT FOR OPEN 
    1. Disconnect variable blower control harness connector.
    2. Check continuity between front blower motor relay harness connector H-2 terminals 5 (W/L) and 7 (W/L) and variable blower control harness connector M122 terminal 1 (W/L).
      Fig 5: Checking Continuity Between Front Blower Motor Relay Harness Connector H2 Terminal 5, 7 & Variable Blower Control Harness Connector M122 Terminal 1
      G02476918Courtesy of NISSAN MOTOR CO., U.S.A.
      • Continuity should exist. 

    OK or NG

    • OK: GO TO 7.
    • NG: Repair harness or connector.
  7. CHECK VARIABLE BLOWER CONTROL SIGNAL CIRCUIT 
    1. Disconnect front air control connector.
    2. Check continuity between front air control connector M50 terminal 40 (O) and variable blower control connector M122 terminal 2 (O).
      Fig 6: Checking Continuity Between Front Air Control Connector M50 Terminal 40 & Variable Blower Control Connector M122 Terminal 2
      G02476919Courtesy of NISSAN MOTOR CO., U.S.A.
      • Continuity should exist. 

    OK or NG

    • OK: GO TO 8.
    • NG: Repair harness or connector.
  8. CHECK FRONT BLOWER MOTOR RELAY (COIL SIDE) POWER SUPPLY 

    Check voltage between front blower motor relay connector H-2 terminal 1 (G/Y) and ground.

    Fig 7: Checking Voltage Between Front Blower Motor Relay Connector H-2 Terminal 1 & Ground
    G02476920Courtesy of NISSAN MOTOR CO., U.S.A.
    • Battery voltage should exist. 

    OK or NG

    • OK: GO TO 9.
    • NG: Repair harness or connector.
  9. CHECK FRONT BLOWER MOTOR RELAY (COIL SIDE) GROUND CIRCUIT 

    Check continuity between front blower motor relay connector H-2 terminal 2 (G/B) and front air control harness connector M49 terminal 26 (G/B).

    Fig 8: Checking Continuity Between Front Blower Motor Relay Connector H-2 Terminal 2 & Front Air Control Harness Connector M49 Terminal 26
    G02476921Courtesy of NISSAN MOTOR CO., U.S.A.
    • Continuity should exist. 

    OK or NG

    • OK: Replace front air control. Refer to "FRONT AIR CONTROL ".
    • NG: Repair harness or connector.
  10. REPLACE FUSES 
    1. Replace fuses.
    2. Activate the front blower motor.
    3. Does fuse blow?

    Yes or No

    • Yes: GO TO 11.
    • No: Inspection End.
  11. CHECK FRONT BLOWER MOTOR POWER SUPPLY CIRCUIT FOR SHORT 
    1. Disconnect front blower motor harness connector.
    2. Check continuity between variable blower control harness connector M122 terminal 1 (W/L) and ground.
      Fig 9: Checking Continuity Between Variable Blower Control Harness Connector M122 Terminal 1 & Ground
      G02476922Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should not exist. 

    OK or NG

    • OK: GO TO 12.
    • NG: Repair harness or connector.
  12. CHECK VARIABLE BLOWER CONTROL SIGNAL CIRCUIT 
    1. Disconnect front air control connector
    2. Check continuity between front air control connector M50 terminal 40 (O) and variable blower control connector M122 terminal 2 (O)
      Fig 10: Checking Continuity Between Front Air Control Connector M50 Terminal 40 & Variable Blower Control Connector M122 Terminal 2
      G02476923Courtesy of NISSAN MOTOR CO., U.S.A.
      • Continuity should exist. 

    OK or NG

    • OK: Check blower motor, if OK replace variable blower control. Refer to "FRONT BLOWER MOTOR RELAY ".
    • NG: Repair harness or connector.
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