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

Window Defogger System - Rear Window Defogger System Does Not Operate. WINDSHIELD / WINDOWGLASS. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

1.CHECK COMMUNICATION SYSTEM

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

Go to step 5

Go to step 9

A

3.REPLACE MULTI-MEDIA MODULE DISPLAY

Replace the multi-media module display.

NEXT

4.CONFIRM REAR WINDOW DEFOGGER OPERATION

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

Go to step 13

NG

10.INSPECT DEFOG RELAY

REPLACE DEFOG RELAY

OK

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

Window Defogger System - Rear Window Defogger System Does Not Operate. WINDSHIELD / WINDOWGLASS. Lexus IS250 IS220d GSE20 ALE20

Disconnect the DEFOG relay.

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

REPAIR OR REPLACE LH-IG FUSE OR HARNESS AND CONNECTOR

OK

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

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

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE A/C AMPLIFIER ASSEMBLY

13.INSPECT DEFOGGER RELAY

REPLACE DEFOG RELAY

OK

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

Disconnect the DEFOG relay.

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

REPAIR OR REPLACE DEFOG FUSE OR HARNESS AND CONNECTOR

OK

15.INSPECT NOISE FILTER

Disconnect the noise filter connectors.

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

REPLACE NOISE FILTER

OK

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

Disconnect the DEFOG relay and defogger wire connectors.

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

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

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPAIR OR REPLACE REAR WINDOW DEFOGGER WIRE

LEXUS IS250, IS220d / GSE20 ALE20

WINDSHIELD / WINDOWGLASS

Lexus IS250 IS220d GSE20 ALE20

WINDOW DEFOGGER SYSTEM

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

Tester Connection	Condition	Specified Condition
1 - Body ground	Engine switch on (IG)	10 to 14 V