Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Automatic High Beam Switch Indicator does not Come ON

DESCRIPTION

When the automatic high beam system is on, the main body ECU (multiplex network body ECU) illuminates the auto high beam switch indicator.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
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PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

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

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

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

Body Electrical > Main Body > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Automatic High Beam Switch Light	Auto high beam switch indicator light	OFF or ON	-

Body Electrical > Main Body > Active Test

Tester Display
Automatic High Beam Switch Light

OK:

Auto high beam switch indicator light illuminates.

USE SIMULATION METHOD TO CHECK

2.	INSPECT AUTO HIGH BEAM SWITCH

(a) Remove the auto high beam switch.

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(b) Inspect the auto high beam switch.

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REPLACE AUTO HIGH BEAM SWITCH

3.	CHECK HARNESS AND CONNECTOR (POWER SOURCE - AUTO HIGH BEAM SWITCH)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
G31-3 (IND+) - Body ground	Always	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (AUTO HIGH BEAM SWITCH - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(a) Disconnect the G32 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
G31-4 (AZBI) - G32-23 (AHID)	Always	Below 1 Ω
G31-4 (AZBI) or G32-23 (AHID) - Body ground	Always	10 kΩ or higher

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

REPAIR OR REPLACE HARNESS OR CONNECTOR

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Toyota Avalon (XX50) 2019-2022 Owners Manual