Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Rear Window Defogger System does not Operate

DESCRIPTION

When the rear window defogger switch on the radio and display receiver assembly is pressed, the operation signal is transmitted to the air conditioning amplifier assembly via CAN communication. When the air conditioning amplifier assembly receives the signal, it turns on the DEF 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.
• If the auxiliary battery voltage becomes low, auxiliary battery load control will operate in order to ensure sufficient power is supplied to the power steering system. In this case, the window defogger system may not operate.

PROCEDURE

(a) Check the air conditioning system.

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

(a) Connect the Techstream to the DLC3.

(b) Turn the power 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.

OK:

The window defogger system operates normally.

NG

GO TO STEP 4

OK

(a) Replace the rear window defogger switch (radio and display receiver assembly) with a new or known good one.

Click here

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

Click here

OK:

The window defogger system operates normally.

OK

END (REAR WINDOW DEFOGGER SWITCH (RADIO AND DISPLAY RECEIVER ASSEMBLY WAS DEFECTIVE))

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Inspect the DEF relay.

Click here

NG

REPLACE DEF RELAY

OK

(a) Remove the DEF relay from the No. 1 engine room relay block and No. 1 junction block assembly.

*a DEF Relay Holder

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

Standard Voltage:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Remove the DEF relay from the No. 1 engine room relay block and No. 1 junction block assembly.

*a DEF Relay Holder

(b) Disconnect the G35 air conditioning amplifier assembly connector.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Remove the DEF relay from the No. 1 engine room relay block and No. 1 junction block assembly.

*a DEF Relay Holder

(b) Disconnect the K21 rear window defogger wire (back window glass) wire connector.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Disconnect the L1 rear window defogger wire (back window glass) connector.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Reconnect the G35 air conditioning amplifier assembly connector.

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

(b) Reinstall the DEF relay.

(c) Remove the air conditioning amplifier assembly with its connectors still connected.

Click here

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

Standard Voltage:

OK

REPAIR OR REPLACE BACK WINDOW GLASS

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY