Rear Window Defogger Circuit Inspection

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

CHECK REAR WINDOW DEFOGGER POWER SUPPLY CIRCUIT 1

Turn ignition switch OFF.
Disconnect condenser.
Turn ignition switch ON.

Check voltage between condenser-3 connector and ground.

REAR WINDOW DEFOGGER POWER SUPPLY CIRCUIT 1

Connector	Terminals		Condition	Voltage (V) (Approx.)
Connector	(+)	(-)	Condition	Voltage (V) (Approx.)
B21	1	Ground	Rear window defogger switch ON.	Battery voltage
B21	1	Ground	Rear window defogger switch OFF.	0

Fig 1: Checking Voltage Between Condenser Connector 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 B351 terminal - and ground.
  Ground: Continuity should exist.
OK or NG

Fig 2: Checking Continuity Between Rear Window Defogger Connector B351 Terminal - And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

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.
NG: Repair or replace harness.
CHECK CONDENSER 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 condenser-3 connector B21 terminal 1.
  5 - 1: Continuity should exist.
Fig 3: Checking Continuity Between Rear Window Defogger Relay Connector B4 Terminal 5 And Condenser Connector B21 Terminal 1
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

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

NG: Repair or replace harness.