FixVault

Rear Window Defogger Switch Circuit Check

WARNING: This page is about a different car, the 2006 Nissan Titan. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK REAR WINDOW DEFOGGER SWITCH OPERATION 

    With CONSULT-II 

    Check ("REAR DEF SW", "IGN ON SW") in DATA MONITOR mode with CONSULT-II.

    When rear window defogger switch is turned to ON 

    REAR DEF SW: ON 

    When ignition switch is turned to ON 

    IGN ON SW: ON 

    Fig 1: CONSULT-II Display - Data Monitor
    G04187921Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

    1. Turn ignition switch ON.
    2. Check voltage between BCM connector and ground.
      Fig 2: Checking Voltage Between BCM Connector And Ground
      G04187922Courtesy of NISSAN MOTOR CO., U.S.A.
      CONNECTOR TERMINAL VOLTAGE CHECK

      Connector Terminals Condition Voltage (V) (Approx.)
      (+) (-)
      M18 9 Ground Rear window defogger switch is pressed. 0
      Rear window defogger switch is OFF. 5

    OK or NG 

    OK: Rear window defogger switch check is OK.

    NG: GO TO 2.

  2. CHECK REAR WINDOW DEFOGGER SWITCH CIRCUIT HARNESS CONTINUITY 
    1. Turn ignition switch OFF.
    2. Disconnect BCM and front air control.
    3. Check continuity between BCM connector M18 terminal 9 and front air control connector M49 terminal 11.

      9 - 11: Continuity should exist. 

    4. Check continuity between BCM connector M18 terminal 9 and ground

      9 - Ground: Continuity should not exist. 

      Fig 3: Checking Continuity Between BCM Connector M18 Terminal 9, Front Air Control Connector M49 Terminal 11 And Ground
      G04187923Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO 3.

    NG: Repair or replace harness.

  3. CHECK BCM OUTPUT SIGNAL 
    1. Connect BCM.
    2. Turn ignition switch ON.
    3. Check voltage between BCM connector M18 terminal 9 and ground.

      9 - Ground: Approx. 5V 

    4. Fig 4: Checking Voltage Between BCM Connector M18 Terminal 9 And Ground
      G04187924Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: Replace front air control. Refer to "CONTROL UNIT ".

    NG: Replace BCM. Refer to "BCM ".