Toyota 4Runner: Rear Window Defogger System does not Operate

Toyota 4Runner Service Manual / Vehicle Exterior / Window / Glass / Window Defogger System / Rear Window Defogger System does not Operate

DESCRIPTION

When the back door power window is fully closed and the rear window defogger switch is turned on, a rear window defogger activation request signal is sent via the LIN communication line to the air conditioning amplifier.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.
Since the window defogger system has functions that use LIN communication, first confirm that there is no malfunction in the communication system by inspecting the LIN communication functions in accordance with the "How to Proceed with Troubleshooting" procedures. Then, conduct the following inspection procedure.
Since the window defogger system does not operate if the back power window is not operating normally, confirm that the back power window of the power window system is operating normally before performing troubleshooting.

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM (DEFOGGER RELAY [REAR])

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

Air Conditioner

Tester Display	Test Part	Control Range	Diagnostic Note
Defogger Relay (Rear)	DEF relay operation	OFF/ON	-

OK:

The DEF relay operates normally.

GO TO STEP 3

2.	REPLACE HEATER CONTROL ASSEMBLY

(a) Temporarily replace the heater control with a new or normally functioning one (See page ).

(b) Check the rear defogger function.

OK:

The window defogger function operates normally.

END (HEATER CONTROL ASSEMBLY IS DEFECTIVE)

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

3.	INSPECT DEF RELAY

(a) Remove the DEF relay from the engine room relay block, junction block.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 - 5	Battery voltage applied between terminals 1 and 2	Below 1 Ω
3 - 5	Battery voltage not applied between terminals 1 and 2	10 kΩ or higher

REPLACE DEF RELAY

4.	CHECK HARNESS AND CONNECTOR (BATTERY - DEF RELAY)

(a) Remove the DEF relay from the engine room relay block, junction block.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
DEF relay terminal 2 - Body ground	Ignition switch off	Below 1 V
DEF relay terminal 2 - Body ground	Ignition switch ON	11 to 14 V
DEF relay terminal 5 - Body ground	Always	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to DEF Relay)

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - DEF RELAY AND BODY GROUND)

(a) Disconnect the F42 air conditioning amplifier connector.

(b) Remove the DEF relay from the engine room relay block, junction block.

Standard Resistance:

Tester Connection	Condition	Specified Condition
DEF relay terminal 1 - F42-38 (RDEF)	Always	Below 1 Ω
F42-14 (GND) - Body ground	Always	Below 1 Ω
F42-38 (RDEF) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Reconnect the F42 air conditioning amplifier connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F42-38 (RDEF) - F42-14 (GND)	Ignition switch ON, defogger switch on	11 to 14 V
F42-38 (RDEF) - F42-14 (GND)	Ignition switch ON, defogger switch off	Below 1 V

Text in Illustration

*a	Component with harness connected (Air Conditioning Amplifier Assembly)

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

7.	CHECK HARNESS AND CONNECTOR (BACK DOOR GLASS - DEF RELAY AND BODY GROUND)

(a) Disconnect the W1 and W2 back door glass (window defogger wire) connectors.

(b) Remove the DEF relay from the engine room relay block, junction block.

Standard Resistance:

Tester Connection	Condition	Specified Condition
DEF relay terminal 3 - W1-1	Always	Below 1 Ω
W2-1 - Body ground	Always	Below 1 Ω
W1-1 - Body ground	Always	10 kΩ or higher

REPLACE BACK DOOR GLASS (WINDOW DEFOGGER WIRE)

REPAIR OR REPLACE HARNESS OR CONNECTOR

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