Rear Window Defogger Circuit Check

WARNING: This page is about a different car, the 2008 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

CHECK REAR WINDOW DEFOGGER POWER SUPPLY CIRCUIT

Turn ignition switch OFF.
Disconnect rear window defogger.
Turn ignition switch ON.

Check voltage between rear window defogger connector D504 terminal + and ground.

TERMINAL VOLTAGE CONDITION CHART

Connector	Terminals		Condition	Voltage (V) (Approx.)
Connector	(+)	(-)	Condition	Voltage (V) (Approx.)
D504	+	Ground	Rear window defogger switch ON.	Battery voltage
D504	+	Ground	Rear window defogger switch OFF.	0

Fig 1: Checking Voltage Between Rear Window Defogger Connector D504 Terminal + And Ground

Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: GO TO 2.

NG: GO TO 3.

CHECK REAR WINDOW DEFOGGER GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between rear window defogger connector D515 terminal - and ground.
  - - Ground : Continuity should exist.
OK or NG

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.
  
  Fig 2: Checking Continuity Between Rear Window Defogger Connector D515 Terminal - And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.
NG: Repair or replace harness.
CHECK REAR WINDOW DEFOGGER HARNESS
1. Turn ignition switch OFF.
2. Disconnect rear window defogger relay.
3. Check continuity between rear window defogger relay connector B4 terminal 5 and rear window defogger connector D504 terminal +.
  5 - + : Continuity should exist.
OK or NG

OK: Check the condition of the harness and the connector.

NG: Repair or replace harness.

Fig 3: Checking Continuity Between Rear Window Defogger Relay Terminal 5 And Rear Window Defogger Terminal +
Courtesy of NISSAN MOTOR CO., U.S.A.