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Home >> Nissan-Datsun >> 2004 >> Altima S, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1075 (Heater & Air Conditioning Control System (Automatic Air Conditioner)) >> DTC/Circuit Diagnosis >> Mode Door Motor >> Mode Door Motor (Front) Diagnosis Procedure

Mode Door Motor (Front) Diagnosis Procedure

WARNING: This page is about a different car, the 2012 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.

Regarding Wiring Diagram information, refer to "WIRING DIAGRAM - AUTOMATIC ".

SYMPTOM:

  1. CHECK MODE DOOR MOTOR POSITION BALANCED RESISTOR (PBR) FEEDBACK VOLTAGE
    1. Turn ignition switch ON.
    2. Using CONSULT, check "MODE FDBCK" in "DATA MONITOR" mode in "HVAC". Refer to "CONSULT FUNCTION (HVAC) ".
    3. Observe "MODE FDBCK" voltage while cycling A/C auto amp. mode switch through all modes.
      Monitor Item Condition Results
      MODE FDBCK Cycle mode switch through all modes, D/F ( ), VENT ( ), B/L ( ), and FOOT( ) Voltage varies between D/F ( ) and VENT ( ), and between VENT ( ) and B/L ( ).

      Is the inspection result normal? 

      YES >>

      NO: GO TO 2.

  2. CHECK MODE DOOR MOTOR CIRCUITS FOR OPEN AND SHORT TO GROUND
    1. Turn ignition switch OFF.
    2. Disconnect the A/C auto amp. harness connector M49 and the mode door motor harness connector M142.
    3. Check continuity between A/C auto amp. harness connector M49 terminals 19, 20 and the mode door motor harness connector M142 terminals 5, 6.
      Connector Terminal Connector Terminal Continuity
      M49 19 M142 6 Yes
      20 1
    4. Check continuity between A/C auto amp. harness connector M49 terminals 19, 20 and ground.
      Connector Terminal - Continuity
      M49 19 Ground No
      20

      Is the inspection result normal? 

      YES: GO TO 3.

      NO: Repair or replace harness as necessary.

  3. CHECK A/C AUTO AMP. FOR MODE DOOR MOTOR POWER AND GROUND
    1. Reconnect A/C auto amp. harness connector.
    2. Turn ignition switch ON.
    3. Press the mode switch to the D/F ( ) mode.
    4. Check voltage between A/C auto amp. harness connector M49 terminal 19 and terminal 20 while pressing the mode switch to the VENT ( ), and then the B/L ( ) mode.
      Connector Terminals Condition Voltage (Approx.)
      (+) (-)
      M49 19 20 D/F ( ) mode to VENT ( ) mode Battery voltage
      20 19 VENT ( ) mode to B/L ( ) mode Battery voltage

      Is the inspection result normal? 

      YES: GO TO 4.

      NO: Replace A/C auto amp. Refer to "REMOVAL AND INSTALLATION ".

  4. CHECK MODE DOOR MOTOR PBR CIRCUITS FOR OPEN AND SHORT TO GROUND
    1. Turn ignition switch OFF.
    2. Disconnect the A/C auto amp. harness connectors.
    3. Check continuity between A/C auto amp. harness connector M49 terminal 3, and M50 terminal 28 and the mode door motor harness connector M142 terminals 2, 3.
      Connector Terminal Connector Terminal Continuity
      M49 3 M142 2 Yes
      M50 28 3
    4. Check continuity between A/C auto amp. harness connector M49 terminal 3, M50 terminal 28 and ground.
      Connector Terminal - Continuity
      M49 3 Ground No
      M50 28

      Is the inspection result normal? 

      YES: GO TO 5.

      NO: Repair or replace harness as necessary.

  5. CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR OPEN AND SHORT TO GROUND
    1. Check continuity between A/C auto amp. harness connector M49 terminal 7 and mode door motor harness connector M142 terminal 4.
      Connector Terminal Connector Terminal Continuity
      M49 7 M142 4 Yes
    2. Check continuity between A/C auto amp. harness connector M49 terminal 7 and ground.
      Connector Terminal - Continuity
      M49 7 Ground No

      Is the inspection result normal? 

      YES: GO TO 6.

      NO: Repair or replace harness as necessary.

  6. CHECK A/C AUTO AMP. FOR 5 VOLT REFERENCE (VREF), VREF RETURN, AND FEEDBACK SIGNAL
    1. Reconnect A/C auto amp. harness connectors.
    2. Turn ignition switch ON.
    3. Check voltage between A/C auto amp. harness connector M49 terminal 3, and M50 terminal 28.
      Connector Terminals Connector Terminals Voltage (Approx.)
      (+) (-)
      M50 28 M49 3 5V
    4. Check voltage between A/C auto amp. harness connector M49 terminal 7 and ground.
      Connector Terminal - Voltage (Approx.)
      M49 7 Ground 0V

      Is the inspection result normal? 

      YES: GO TO 7.

      NO: Replace A/C auto amp.. Refer to "REMOVAL AND INSTALLATION ".

  7. CHECK A/C AUTO AMP. FOR FEEDBACK SIGNAL
    1. Reconnect the mode door motor harness connector M142.
    2. Check voltage between A/C auto amp. harness connector M49 terminal 7 and ground.
      Connector Terminal - Voltage (Approx.)
      M49 7 Ground 0.2 to 4.8V

      Is the inspection result normal? 

      YES: Inspect mode door for binding or mechanical failure. If mode door moves freely, replace A/C auto amp.. Refer to "REMOVAL AND INSTALLATION ".

      NO: Replace the mode door motor. Refer to "REMOVAL AND INSTALLATION ".

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