Lexus NX: Rear Window Defogger System does not Operate

Lexus NX Service Manual / Vehicle Exterior / Window / Glass / Window Defogger System / Rear Window Defogger System does not Operate

DESCRIPTION

When the rear window defogger switch on the air conditioning control assembly is pressed, the operation signal is transmitted to the air conditioning amplifier assembly via LIN communication. When the air conditioning amplifier assembly receives the signal, it turns on the defogger relay to operate the window defogger system.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • The window defogger system uses the LIN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the window defogger system after confirming that the communication system is functioning properly.

    Click here

  • If the auxiliary battery voltage becomes low, windshield deicer operation is canceled to prioritize supplying power to the power steering system.

    for Power Tilt and Power Telescopic Steering Column: Click here

    for Manual Tilt and Manual Telescopic Steering Column: Click here

PROCEDURE

1.

CHECK AIR CONDITIONING SYSTEM

(a) Check the air conditioning system.

Click here

HINT:

Both the window defogger system operation signal and air conditioning system operation signal are transmitted to the air conditioning amplifier assembly via the same communication line.

OK:

The air conditioning system operates normally.

NG

GO TO AIR CONDITIONING SYSTEM

OK

2.

CHECK AIR CONDITIONING CONTROL ASSEMBLY

(a) Check that the defogger indicator illuminates when the window defogger switch is on.

OK:

Defogger indicator illuminates.

NG

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

OK

3.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Using the Techstream, perform the Active Test.

Click here

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Defogger Relay (Rear)

Defogger relay

OFF or ON

-

Body Electrical > Air Conditioner > Active Test

Tester Display

Defogger Relay (Rear)

OK:

Back door glass (defogger wire) warms up.

NG

GO TO STEP 5

OK

4.

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Temporarily replace the air conditioning amplifier assembly with a new or normally functioning one.

Click here

(b) Check that the window defogger system operates normally.

OK:

The window defogger system operates normally.

OK

END (AIR CONDITIONING AMPLIFIER ASSEMBLY IS DEFECTIVE)

NG

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

5.

CHECK HARNESS AND CONNECTOR (BACK DOOR GLASS - BATTERY)

(a) Disconnect the back door glass (defogger wire) connector.

*a

Front view of wire harness connector

(to Back Door Glass [Defogger Wire])

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

Y1-1 (B) - Body ground

Power switch on (IG), rear window defogger switch on

11 to 14 V

Power switch on (IG), rear window defogger switch off

Below 1 V

OK

REPLACE BACK DOOR GLASS (DEFOGGER WIRE)

NG

6.

INSPECT DEFOGGER RELAY

(a) Remove the defogger relay from the No. 2 engine room relay block.

(b) Inspect the defogger relay.

Click here

NG

REPLACE DEFOGGER RELAY

OK

7.

CHECK HARNESS AND CONNECTOR (DEFOGGER RELAY - BATTERY)

(a) Remove the defogger relay from the No. 2 engine room relay block.

*a

Front view wire harness connector

(to Defogger Relay)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

Defogger relay terminal 2 - Body ground

Power switch on (IG)

11 to 14 V

Defogger relay terminal 5 - Body ground

Power switch off

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.

CHECK HARNESS AND CONNECTOR (DEFOGGER RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY AND BACK DOOR GLASS)

(a) Remove the defogger relay from the No. 2 engine room relay block.

(b) Disconnect the Y1 back door glass (defogger wire) connector.

(c) Disconnect the I50 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Defogger relay terminal 1 - I50-38 (RDFG)

Always

Below 1 Ω

Defogger relay terminal 3 - Y1-1 (B)

Always

Below 1 Ω

Defogger relay terminal 1 or I50-38 (RDFG) - Body ground

Always

10 kΩ or higher

Defogger relay terminal 3 or Y1-1 (B) - Body ground

Always

10 kΩ or higher

OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

READ NEXT:

 Windshield Deicer System

 Parts Location

PARTS LOCATION ILLUSTRATION *1 FRONT WIPER DEICER RELAY *2 AIR CONDITIONING AMPLIFIER ASSEMBLY *3 MULTI-DISPLAY ASSEMBLY *4 RADIO RECEIVER ASSEMBLY *5 WINDSHIELD GLASS - WIND

 System Diagram

SYSTEM DIAGRAM Communication Table Transmitter Receiver Signal Communication Method Multi-display Assembly Radio Receiver Assembly Windshield deicer switch signal GVIF Radio Re

SEE MORE:

 Wireless Charger Power Source Circuit

DESCRIPTION This is the power source circuit to operate the mobile wireless charger cradle assembly. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: Inspect the fuses for circuits related to this system before performing the following inspection procedure. PROCEDURE 1. CHECK HARNESS AND CONNEC

 Abnormal Zero Point of Steering Angle Sensor (C1290)

DESCRIPTION The skid control ECU (brake booster with master cylinder assembly) acquires the steering sensor zero point every time the power switch is turned on (READY) and the vehicle is driven at 35 km/h (22 mph) or more for approximately 5 seconds. The skid control ECU (brake booster with master c

© 2016-2024 Copyright www.lexunx.com