2003 Infiniti FX45FACTORY OEM SERVICE PROCEDURE

Rear Window Defogger Circuit Check

  1. CHECK POWER SUPPLY CIRCUIT 1 
    1. Turn ignition switch OFF.
    2. Disconnect rear window defogger connector.
    3. Turn ignition switch ON.
    4. Check voltage between rear window defogger connector and ground.
      Fig 1: Checking Rear Window Defogger Power Supply Circuit
      G03107412Courtesy of NISSAN MOTOR CO., U.S.A.
      REAR WINDOW DEFOGGER CIRCUIT VOLTAGE

      Connector Terminal (Wire color) Condition Voltage (V) (Approx.)
      (+) (-)
      D104 1(W) Ground Rear window defogger switch ON. Battery voltage
      Rear window defogger switch OFF. 0

    OK or NG

    1. OK: GO TO 2.
    2. NG: GO TO  3 .
  2. CHECK GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Check continuity between rear window defogger connector D114 terminal 2 and ground.
      Fig 2: Checking Rear Window Defogger Ground Circuit
      G03107413Courtesy of NISSAN MOTOR CO., U.S.A.

      2 (B) - Ground: Continuity should exist. 

    OK or NG

    1. OK: Check filament. Refer to FILAMENT CHECK  .
      • If filament is OK, check condition of harness and connector.
      • If filament is NG, repair filament.
    2. NG: Repair or replace harness between rear window defogger and ground.
  3. CHECK HARNESS CONTINUITY 
    1. Turn ignition switch OFF.
    2. Remove rear window defogger relay.
    3. Check continuity between rear window defogger relay connector E13 terminal 5, 7 and rear window defogger connector D104 terminal 1.
      Fig 3: Checking Rear Window Defogger Harness Continuity
      G03107414Courtesy of NISSAN MOTOR CO., U.S.A.

      5 (B) - 1 (W): Continuity should exist. 

      7 (B) - 1 (W): Continuity should exist. 

      OK or NG

    1. OK: Check condition of harness and connector.
    2. NG: Repair or replace harness rear window defogger relay and condenser.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.