Rear Window Defogger Circuit Check

WARNING: This page is about a different car, the 2005 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.

CHECK REAR WINDOW DEFOGGER 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: Rear Window Defogger Connector & Ground Voltage Chart
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 2.
2. NG: GO TO 3
Fig 2: Checking Voltage Between Rear Window Defogger Connector Terminal 2 & Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK REAR WINDOW DEFOGGER GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between rear window defogger connector B451 terminal 1 and ground.
  1 (B) - Ground: Continuity should exist
OK or NG
1. OK: Check filament, Refer to FILAMENT CHECK .
  - If filament is OK. Check the condition of the harness and the connector.
  - If filament is NG. Repair filament.
2. NG: Repair or replace harness.
Fig 3: Checking Continuity Between Rear Window Defogger Connector B451 Terminal 1 & Ground
Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK REAR WINDOW DEFOGGER POWER WINDOW SUPPLY CIRCUIT 2
1. Turn ignition switch OFF.
2. Disconnect condenser connector.
3. Turn ignition switch ON.
4. Check voltage between condenser connector and ground.
  
  Fig 4: Condenser Connector & Ground Voltage Chart
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 5: Checking Voltage Between Condenser Connector & Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: Repair or replace harness.
2. NG: GO TO 4.
CHECK CONDENSER HARNESS
1. Turn ignition switch OFF.
2. Disconnect rear window defogger relay.
3. Check continuity between rear window defogger relay connector B417 terminal 5 and condenser connector B416 terminal 1.
  5 (L) - 1 (L): Continuity should exist.
OK or NG
1. OK: Check the condition of the harness and the connector.
2. NG: Repair or replace harness.
Fig 6: Checking Continuity Between Rear Window Defogger Relay Connector B417 Terminal 5 & Condenser Connector B416 Terminal 1
Courtesy of NISSAN MOTOR CO., U.S.A.