Rear Window Defogger Signal 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 SIGNAL CIRCUIT

Turn ignition switch ON.

Check voltage between unified meter and A/C amp. connector and ground.

REAR WINDOW DEFOGGER SIGNAL CIRCUIT

Connector	Terminals		Condition	Voltage (V) (Approx.)
Connector	(+)	(-)	Condition	Voltage (V) (Approx.)
M89	56	Ground	Rear window defogger switch ON	Battery voltage
M89	56	Ground	Rear window defogger switch OFF	0

Fig 1: Checking Voltage Between Connector Terminal 56 And Ground

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

OK or NG

OK: Check multiplex communication circuit. Refer to "MULTIPLEX COMMUNICATION CIRCUIT ".

NG: GO TO 2.

CHECK REAR WINDOW DEFOGGER SIGNAL CIRCUIT HARNESS CONTINUITY
1. Turn ignition switch OFF.
2. Disconnect rear window defogger relay and unified meter and A/C amp.
3. Check continuity between rear window defogger relay connector B4 (A) terminal 7 and unified meter and A/C amp. connector M89 (B) terminal 56.
  7 - 56: Continuity should exist.
4. Check continuity between rear window defogger relay connector B4 (A) terminal 7 and ground
  7 - Ground: Continuity should not exist.
Fig 2: Checking Rear Window Defogger Signal Circuit Harness Continuity
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG

OK: Check rear window defogger power supply. Refer to "REAR WINDOW DEFOGGER POWER SUPPLY CIRCUIT CHECK ".

NG: Repair or replace harness.