Rear Window Defogger Switch

REAR WINDOW DEFOGGER SWITCH

Description

- The rear window defogger is operated by pressing the rear window defogger switch ON.
- The indicator lamp in the rear window defogger switch illuminates while the rear window defogger is ON.


Component Function Check


1. CHECK REAR WINDOW DEFOGGER SWITCH FUNCTION

1.Push ignition switch to ON.
2.Press rear window defogger switch.
3.Check that the indicator lamp of the rear window defogger switch illuminates.
4.Press rear window defogger switch.
5.Check that the indicator lamp of the rear window defogger switch extinguishes.
Is the inspection result normal?
YES- Rear window defogger switch function is OK.
NO- Refer to "Diagnosis Procedure".


Diagnosis Procedure

Regarding Wiring Diagram information, Rear Window Defogger Coupe (Coupe) or Rear Window Defogger Sedan (Sedan).

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

DEF
Check if Fuse 13 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 13 and ground.
2.While pressing the rear window defogger switch ON and OFF, check for voltage between Fuse 13 and ground.





Is the inspection result normal?
YES- GO TO 4
NO- Perform rear window defogger relay component inspection. Rear Window Defogger Relay. If OK, repair fuse block as necessary.

4. CHECK REAR WINDOW DEFOGGER SWITCH INDICATOR CIRCUIT

1.Press rear window defogger switch.
2.Check for voltage between front air control connector and ground.





Is the inspection result normal?
YES- Replace front air control. Service and Repair.
NO- Repair or replace harness.

5. CHECK FRONT AIR CONTROL (REAR WINDOW DEFOGGER SWITCH) FUNCTION

CONSULT
1.Select BCM (REAR DEFOGGER) DATA MONITOR.
2.While pressing and releasing the rear window defogger switch, check that the switch state changes between ON and OFF.

REAR DEF SW: ON
REAR DEF SW: OFF

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 M18 terminal 38 and ground.





Is the inspection result normal?
YES- Replace BCM. 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 front air control connector.





4.Check continuity between BCM harness connector M18 terminal 38 and ground.





Is the inspection result normal?
YES- Replace front air control. Service and Repair.
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 M4 terminal 4Q and ground.

REAR DEFOGGER: ON
REAR DEFOGGER: OFF





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 M4 terminal 4Q 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.
DEF
2.Disconnect BCM and fuse block (J/B).
3.Check continuity between BCM connector M18 terminal 59 and fuse block (J/B) connector M4 terminal
4Q.





4.Check continuity between fuse block (J/B) connector M4 terminal 4Q and ground.





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

11. CHECK REAR WINDOW DEFOGGER RELAY

Check rear window defogger relay.
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.
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.