Rear Window Defogger Switch Circuit Check

WARNING: This page is about a different car, the 2003 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.

CHECK REAR WINDOW DEFOGGER SWITCH OPERATION
With CONSULT-II

Check ("REAR DEF SW", "IGN ON SW") in DATA MONITOR mode with CONSULT-II. Refer to GW-75.
1. When rear defogger switch is turned to ON REAR DEF SW: ON
2. When ignition switch is turned to ON IGN ON SW: ON
  
  Fig 1: DATA MONITOR mode Display On CONSULT-II
  Courtesy of NISSAN MOTOR CO., U.S.A.
With out CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between BCM connector ground.
  
  Fig 2: Terminal Voltage Condition Table
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 3: Checking Voltage Between BCM Connector Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG

OK: Rear window defogger switch check is OK.

NG: GO TO 2
CHECK REAR WINDOW DEFOGGER SWITCH CIRCUIT HARNESS CONTINUITY
1. Turn ignition switch OFF.
2. Disconnect BCM and A/C and audio connector.
3. Check continuity between BCM connector M3 terminal 69 and A/C and audio connector M38 terminal 12.
  1. 69 (L/R) - 12(L/R): Continuity should exist
    
    Fig 4: Checking Rear Window Defogger Switch Circuit Harness Continuity (Terminal 69-12 And 69-Ground
    Courtesy of NISSAN MOTOR CO., U.S.A.
4. Check continuity between BCM connector M3 terminal 69 and ground
  1. 69 (L/R) - Ground: Continuity should not exist
OK or NG

OK: GO TO 3.

NG: Repair or replace harness between BCM and A/C and audio controller.
CHECK BCM OUTPUT SIGNAL
1. Connect BCM connector.
2. Turn ignition switch ON.
3. Check voltage between BCM connector M3 terminal 69 and ground.
  1. 69 (L/R) - Ground: Approx. 5
  Fig 5: Checking BCM Output Signal (Terminal 69-Ground)
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG

OK: GO TO 3.

NG: Replace BCM.
CHECK REAR WINDOW DEFOGGER SWITCH
1. Connect A/C and audio controller connector.
2. Check continuity between A/C and audio controller connector M38 terminal 3 and 12.
  
  Fig 6: Terminal Condition Continuity Table
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 7: Checking Continuity Between A/C And Audio Controller Connector M38 Terminal 3 - 12
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG

OK: Rear window defogger switch circuit is OK.

NG: Replace A/C and audio controller.