Lexus IS250 · Service Manual BODY

Rear Window Defogger System does not Operate

Circuit diagnosis

DESCRIPTION

with Navigation System:
When the rear window defogger switch, which is built into the multi-media module display assembly, is operated, the operation signals are transmitted to the A/C amplifier assembly through AVC-LAN and BEAN. When the A/C amplifier assembly receives the signals, it turns on the DEFOG relay to operate the rear window defogger.

without Navigation System:
When the rear window defogger switch, which is built into the integration control & panel, is operated, the operation signals are transmitted to the A/C amplifier assembly through AVC-LAN and BEAN. When the A/C amplifier assembly receives the signals, it turns on the DEFOG relay to operate the rear window defogger.


WIRING DIAGRAM

B114228E02

INSPECTION PROCEDURE


1. CHECK COMMUNICATION SYSTEM

  1. Select the DTC check on the intelligent tester to check for communication errors.

    Result:
    Not output DTC codes
    		 A
    Output DTC codes (Multiplex communication)
    		 B
    Output DTC codes (CAN communication)
    		 C



B
GO TO MULTIPLEX COMMUNICATION SYSTEM

C
GO TO CAN COMMUNICATION SYSTEM
A


2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER

  1. Select the ACTIVE TEST, use the intelligent tester to issue a control command, and then check the window defogger operation.

    Air Conditioner:
    Item
    		 Test Details
    Defogger Relay (Rear)
    		 Turns rear window defogger OFF/ON


    Result:
    OK (with Navigation System)
    		 A
    OK (without Navigation System)
    		 B
    NG
    		 C



B
Go to step 5

C
Go to step 9
A


3. REPLACE MULTI-MEDIA MODULE DISPLAY

  1. Replace the multi-media module display.


NEXT


4. CONFIRM REAR WINDOW DEFOGGER OPERATION

  1. Turn the engine switch on (IG), press the defogger switch, and check that window defogger operates.



 NG
REPLACE A/C AMPLIFIER ASSEMBLY
OK

END

5. REPLACE INTEGRATION CONTROL & PANEL

  1. Replace the integration control & panel.


NEXT


6. CONFIRM REAR WINDOW DEFOGGER OPERATION

  1. Turn the engine switch on (IG), press the defogger switch, and check that window defogger operates.



 OK
END
NG


7. REPLACE RADIO RECEIVER ASSEMBLY

  1. Replace the radio receiver assembly.


NEXT


8. REAR WINDOW DEFOGGER OPERATION

  1. Turn the engine switch on (IG), press the defogger switch, and check that window defogger operates.



 NG
REPLACE A/C AMPLIFIER ASSEMBLY
OK

END

9. PERFORM ACTIVE TEST BY INTELLIGENT TESTER

  1. Select the ACTIVE TEST, use the intelligent tester to issue a control command, and then check the DEFOG relay operation.

  1. Check that operation sound of the DEFOG relay is heard.

    Result:
    Relay operating sound is heard
    		 OK
    Relay operating sound is not heard
    		 NG



OK
Go to step 13
NG


10. INSPECT DEFOG RELAY
Click here


NG
REPLACE DEFOG RELAY
OK


11. CHECK WIRE HARNESS (DEFOG RELAY - BATTERY POSITIVE)

  1. B101528E01
    Disconnect the DEFOG relay.

  1. Measure the voltage according to the value(s) in the table below.

    Voltage:
    Engine room No. 1 R/B, J/B:
    Tester Connection
    		 Condition
    		 Specified Condition
    1 - Body ground
    		 Engine switch on (IG)
    		 10 to 14 V



NG
REPAIR OR REPLACE LH-IG FUSE OR HARNESS AND CONNECTOR
OK


12. CHECK WIRE HARNESS (DEFOG RELAY - A/C AMPLIFIER ASSEMBLY)

  1. B126280E01
    Disconnect the DEFOG relay and A/C amplifier assembly connector.

  1. Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    2 - J58-3
    		 Always
    		 Below 1 Ω
    2 - Body ground
    		 Always
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE A/C AMPLIFIER ASSEMBLY

13. INSPECT DEFOGGER RELAY
Click here


NG
REPLACE DEFOG RELAY
OK


14. CHECK WIRE HARNESS (DEFOG RELAY - BATTERY POSITIVE AND BODY GROUND)

  1. B101528E01
    Disconnect the DEFOG relay.

  1. Measure the voltage and resistance according to the value(s) in the table below.

    Resistance:
    Engine room No. 1 R/B, J/B:
    Tester Connection
    		 Condition
    		 Specified Condition
    4 - Body ground
    		 Always
    		 Below 1 Ω

    Voltage:
    Engine room No. 1 R/B, J/B:
    Tester Connection
    		 Condition
    		 Specified Condition
    5 - Body ground
    		 Engine switch on (IG)
    		 10 to 14 V



NG
REPAIR OR REPLACE DEFOG FUSE OR HARNESS AND CONNECTOR
OK


15. INSPECT NOISE FILTER

  1. B118922E01
    Disconnect the noise filter connectors.

  1. Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    A1 - B1
    		 Always
    		 Below 1 Ω
    A1 - Body ground
    		 Always
    		 10 kΩ or higher



NG
REPLACE NOISE FILTER
OK


16. CHECK WIRE HARNESS (DEFOG RELAY - NOISE FILTER)

  1. B105020E02
    Disconnect the DEFOG relay and defogger wire connectors.

  1. Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    3 - Q21-1
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


17. CHECK WIRE HARNESS (DEFOGGER WIRE CONNECTOR - BODY GROUND)

  1. B127529E01
    Measure the resistance according to the value(s) in the table below.

    Resistance:
    Tester Connection
    		 Condition
    		 Specified Condition
    P19-1 - Body ground
    		 Always
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPAIR OR REPLACE REAR WINDOW DEFOGGER WIRE


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