Toyota Tundra Service Manual: Rear Window Defogger System does not Operate

Toyota Tundra Service Manual / Vehicle Interior / Window / Glass / Window Defogger System / Rear Window Defogger System does not Operate

DESCRIPTION

When the air conditioning control assembly (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. Then the air conditioning amplifier operates the rear window defogger.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

This circuit uses the LIN communication line. Before performing the inspection, check that the LIN communication system is functioning normally (see page ).

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM (DEFOGGER RELAY)

(a) Select the Active Test, using the Techstream to generate a control command, and then check that the rear window defogger operates (See page ).

Air Conditioner

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

OK:

Rear window defogger operates normally.

GO TO STEP 3

2.	CHECK AIR CONDITIONING CONTROL ASSEMBLY

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

(b) Check that the malfunction disappears.

OK:

Malfunction disappears.

END (AIR CONDITIONING CONTROL ASSEMBLY IS DEFECTIVE)

REPLACE AIR CONDITIONING AMPLIFIER

3.	INSPECT DEFOGGER RELAY (DEF)

(a) Remove the defogger relay (DEF) 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 - 4	When battery voltage is not applied between terminals 1 and 2	Below 1 Ω
3 - 5		10 kΩ or higher
3 - 4	When battery voltage is applied to terminals 1 and 2	10 kΩ or higher
3 - 5	When battery voltage is applied to terminals 1 and 2	Below 1 Ω

REPLACE DEFOGGER RELAY

4.	CHECK HARNESS AND CONNECTOR (DEFOGGER RELAY - BATTERY AND AIR CONDITIONING AMPLIFIER)

*a	Component without relay connected (Engine Room Relay Block, Junction Block)

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

(b) Disconnect the J19 air conditioning amplifier connector.

Standard Voltage:

Tester Connection	Condition	Specified Condition
Defogger relay (DEF) terminal 2 - Body ground	Ignition switch ON	11 to 14 V
Defogger relay (DEF) terminal 2 - Body ground	Ignition switch OFF	Below 1 V
Defogger relay (DEF) terminal 5 - Body ground	Always	11 to 14 V

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
Defogger relay (DEF) terminal 1 - J19-38 (RDEF)	Always	Below 1 Ω
Defogger relay (DEF) terminal 1 or J19-38 (RDEF) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK HARNESS AND CONNECTOR (DEFOGGER WIRE - DEFOGGER RELAY AND BODY GROUND)

(a) Disconnect the P9 and P10 rear window glass (defogger wire) connectors.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
P9-1 (B) - Defogger relay (DEF) terminal 3	Always	Below 1 Ω
P10-1 (E) - Body ground	Always	Below 1 Ω
Defogger relay (DEF) terminal 4 - Body ground	Always	Below 1 Ω
P9-1 (B) or Defogger relay (DEF) terminal 3 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	CHECK BACK WINDOW GLASS (DEFOGGER WIRE)

(a) Perform the on-vehicle inspection, check that the window defogger system operates normally (See page ).

OK:

Malfunction disappears.

REPLACE AIR CONDITIONING AMPLIFIER

REPAIR DEFOGGER WIRE

Problem Symptoms Table

System Description

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