Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Windshield Deicer does not Operate

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Exterior / Window / Glass / Windshield Deicer System / Windshield Deicer does not Operate

DESCRIPTION

When the front wiper deicer switch assembly is operated, the operation signal is transmitted to the air conditioning amplifier assembly directly. When the air conditioning amplifier assembly receives the signal, it turns on the semiconductor pwr integration ECU to operate the windshield deicer system.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • If the battery voltage is low, the windshield deicer system may not operate. When "Operation of Electrical Items Restricted." is not displayed on the multi-information display in the combination meter assembly, check the Data List item "Battery Control Count (Body ECU)".

    Click here

  • The windshield deicer system uses the CAN communication system. First, confirm that there are no malfunctions in the CAN communication system. Refer to How to Proceed with Troubleshooting.

    Click here

PROCEDURE

1.

CHECK AIR CONDITIONING SYSTEM

(a) Check that the air conditioning system can be operatedusing the remote touch.

HINT:

Both the windshield deicer system operation signal and airconditioning system operation signal are transmitted to the airconditioning amplifier assembly through samecommunication line.

OK:

The air conditioning system operates normally.

NG

GO TO AIR CONDITIONING SYSTEM

OK

2.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Deicer Relay (Front)

Windshield deicer wire (windshield glass)

OFF or ON

-
Body Electrical > Air Conditioner > Active Test

Tester Display

Deicer Relay (Front)

OK:

The windshield deicer system operates normally.

NG

GO TO STEP 5

OK

3.

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Replace the air conditioning amplifier assembly with anew or known good one.

Click here

(b) Check that the windshield deicer system operatesnormally.

OK:

The windshield deicer system operates normally.

OK

END (AIR CONDITIONING AMPLIFIER ASSEMBLY WAS DEFECTIVE)
NG

4.

REPLACE RADIO RECEIVER ASSEMBLY

(a) Replace the radio receiver assembly with anew or known good one.

Click here

(b) Check that the windshield deicer system operatesnormally.

OK:

The windshield deicer system operates normally.

OK

END (RADIO RECEIVER ASSEMBLY WAS DEFECTIVE)
NG

REPLACE MULTI-DISPLAY ASSEMBLY

5.

CHECK SEMICONDUCTOR POWER INTEGRATION ECU

(a) Using a voltmeter, check the signal reading of the semiconductor pwr integration ECU.

Click here

OK:

Output signal reading is normal.

NG

INSPECT SEMICONDUCTOR POWER INTEGRATION ECU (RESULTS OF SIGNAL READING CHECK)

OK

6.

CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU POWER SOURCE AND BODY GROUND)

(a) Remove the semiconductor pwr integration ECU from the engine room relay block.

Click here

*a

Component without semiconductor pwr integration ECU

(Engine Room Relay Block)

-

-

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

B-1 (BATT) - Body ground

Always

11 to 14 V

A-1 (ALT) - Body ground

Always

11 to 14 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1D-14 (GND1) - Body ground

Always

Below 1 Ω

1G-5 (GND2) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

7.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - SEMICONDUCTOR PWR INTEGRATION ECU)

(a) Disconnect the J43 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J43-17 (FDEF) - 1D-6 (-S)

Always

Below 1 Ω

J43-17 (FDEF) or 1D-6 (-S) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

8.

CHECK SEMICONDUCTOR POWER INTEGRATION ECU

(a) Install the semiconductor pwr integration ECU.

Click here

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J43-17 (FDEF) - Body ground

Engine switch on (IG), Front wiper deicer switch off

11 to 14 V

*a

Front view of wire harness connector

(to Air Conditioning Amplifier Assembly)
NG

REPLACE SEMICONDUCTOR POWER INTEGRATION ECU

OK

9.

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Reconnect the J43 air conditioning amplifier assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

J43-17 (FDEF) - J43-4 (GND)

Engine switch on (IG), Front wiper deicer switch on

Below 2.2 V

J43-17 (FDEF) - J43-4 (GND)

Engine switch on (IG), Front wiper deicer switch off

11 to 14 V

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)
NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

OK

10.

CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - WINDSHIELD DEICER WIRE (WINDSHIELD GLASS))

(a) Disconnect the 1E semiconductor pwr integration ECU connector.

(b) Disconnect the A29 windshield deicer wire (windshield glass) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1E-8 (L) - A29-1 (B2)

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

11.

CHECK SEMICONDUCTOR POWER INTEGRATION ECU

(a) Reconnect the 1E semiconductor pwr integration ECU connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

aA1-A29-1 (B2) - Body ground

Engine switch on (IG), Front wiper deicer switch off

Below 1 V

aA1-A29-1 (B2)- Body ground

Engine switch on (IG), Front wiper deicer switch on

11 to 14 V

*a

Front view of wire harness connector

(to Windshield Deicer Wire (Windshield Glass))
NG

REPLACE SEMICONDUCTOR POWER INTEGRATION ECU

OK

12.

CHECK HARNESS AND CONNECTOR (WINDSHIELD DEICER WIRE (WINDSHIELD GLASS) - BODY GROUND)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A29-2 (E) - Body ground

Always

Below 1 Ω
OK

REPLACE WINDSHIELD DEICER WIRE (WINDSHIELD GLASS)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
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