Diagnosis Procedure

REAR WINDOW DEFOGGER SWITCH

WITH AUTO A/C : Diagnosis Procedure

Regarding Wiring Diagram information, refer to "Wiring Diagram" [1][2]Electrical Diagrams.

1. CHECK REAR WINDOW DEFOGGER RELAY OPERATION

1.Push the ignition switch to ON.
2.Check that an operation noise of rear window defogger relay [located in fuse block (J/B)] can be heard when pressing the rear window defogger switch ON and OFF.
Is the inspection result normal?
YES- GO TO 2.
NO- GO TO 5.

2. CHECK FUSE

Check if Fuse 22 from the rear window defogger relay output is blown.
Is the fuse blown?
YES- Replace the blown fuse after repairing the affected circuit.
NO- GO TO 3.

3. CHECK FOR VOLTAGE FROM THE REAR WINDOW DEFOGGER RELAY

1.Connect a voltmeter between Fuse block (J/B) and ground.
2.While pressing the rear window defogger switch ON and OFF, check for voltage between Fuse block (J/B)
and ground.





Is the inspection result normal?
YES- GO TO 4.
NO- Perform rear window defogger relay diagnosis. Refer to "Diagnosis Procedure" Rear Window Defogger Relay.

4. CHECK REAR WINDOW DEFOGGER SWITCH INDICATOR CIRCUIT

1.Press rear window defogger switch.
2.Check for voltage between A/C auto amp. connector and ground.





Is the inspection result normal?
YES- Replace A/C auto amp. Refer to "Removal and Installation" Removal And Installation.
NO- Repair or replace harness.

5. CHECK A/C AUTO AMP. (REAR WINDOW DEFOGGER SWITCH) FUNCTION

1.Check ("REAR DEF SW") in BCM - REAR DEFOGGER "DATA MONITOR" mode by using CONSULT.
2.Operate rear window defogger switch and check the status on CONSULT screen.





Is the inspection result normal?
YES- GO TO 8.
NO- GO TO 6.

6. CHECK REAR WINDOW DEFOGGER ON SIGNAL CIRCUIT

Check voltage between BCM connector and ground.





Is the inspection result normal?
YES- Replace BCM. Refer to "Removal and Installation" Service and Repair.
NO- GO TO 7.

7. CHECK HARNESS CONTINUITY

1.Push ignition switch to OFF.
2.Disconnect BCM and front air control.
3.Check continuity between BCM connector and A/C auto amp.





4.Check continuity between BCM harness connector and ground.





Is the inspection result normal?
YES- Replace A/C auto amp. Refer to "Removal and Installation" Removal And Installation.
NO- Repair or replace harness.

8. CHECK REAR WINDOW DEFOGGER RELAY GROUND CIRCUIT

CONSULT
1.Select BCM (REAR DEFOGGER) ACTIVE TEST.
2.Turn REAR DEFOGGER active test ON and OFF.
3.Check voltage between fuse block (J/B) connector and ground.





Is the inspection result normal?
YES- GO TO 11.
NO- GO TO 9.

9. CHECK REAR WINDOW DEFOGGER RELAY CIRCUIT

Check voltage between fuse block (J/B) connector and ground.





Is the inspection result normal?
YES- Replace rear window defogger relay.
NO- GO TO 10.

10. CHECK HARNESS CONTINUITY

1.Push ignition switch to OFF.
2.Disconnect BCM and fuse block (J/B).
3.Check continuity between BCM connector and fuse block (J/B) connector.





4.Check continuity between fuse block (J/B) connector M5 terminal 6P and ground.





Is the inspection result normal?
YES- Perform rear window defogger relay component inspection. Refer to "Component Inspection" Rear Window Defogger Relay. If OK, replace BCM. Refer to "Removal and Installation" Service and Repair.
NO- Repair or replace harness.

11. CHECK REAR WINDOW DEFOGGER RELAY

Check rear window defogger relay.
Refer to "Component Inspection" Rear Window Defogger Relay.
Is the inspection result normal?
YES- GO TO 12.
NO- Replace rear window defogger relay.

12. CHECK INTERMITTENT INCIDENT

Check intermittent incident.
Refer to "Intermittent Incident" Intermittent Incident.
Is the inspection result normal?
YES-Check the following.
- Battery power supply circuit.
- Fuse block (J/B).
NO- Repair or replace the malfunctioning parts.