Last Modified: 08-21-2023 6.11:8.1.0 Doc ID: RM1000000019XNL
Model Year Start: 2019 Model: Avalon Prod Date Range: [04/2018 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model): Blower Motor Circuit; 2019 - 2022 MY Avalon [04/2018 -        ]

Blower Motor Circuit

DESCRIPTION

The blower motor with fan sub-assembly is operated by signals from the air conditioning amplifier assembly. Blower motor speed signals are transmitted in accordance with changes in the duty ratio.

If the airflow volume is low or the blower speed cannot be changed, the following factors may be the cause.

Symptom

Factor

Airflow volume cannot be changed
  • Air conditioning amplifier assembly malfunction
  • Blower motor with fan sub-assembly malfunction
  • Harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine 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.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Blower Motor

Blower motor with fan sub-assembly

Min.: 0

Max.: 31

-

Body Electrical > Air Conditioner > Active Test

Tester Display

Blower Motor

Result

Proceed to

Blower motor with fan sub-assembly does not operate

A

Blower motor with fan sub-assembly operates but does not change speed

B
B

GO TO STEP 5

A

2.

CHECK HARNESS AND CONNECTOR (BLOWER MOTOR WITH FAN SUB-ASSEMBLY - POWER SOURCE AND BODY GROUND)

(a) Disconnect the A16 blower motor with fan sub-assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A16-3 (+B) - Body ground

Always

11 to 14 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

A16-1 (GND) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK HARNESS AND CONNECTOR (BLOWER MOTOR WITH FAN SUB-ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A16-2 (SI) - G35-6 (BLW)

Always

Below 1 Ω

A16-2 (SI) or G35-6 (BLW) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

INSPECT BLOWER MOTOR WITH FAN SUB-ASSEMBLY

*a

Front view of wire harness connector

(to Air Conditioning Amplifier Assembly)

(a) Connect the A16 blower motor with fan sub-assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

G35-6 (BLW) - Body ground

Always

4.75 to 5.25 V
NG

REPLACE BLOWER MOTOR WITH FAN SUB-ASSEMBLY

OK

5.

INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)

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

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

(c) Set the blower speed to LO.

(d) Using an oscilloscope, check the waveform.

Item

Content

Terminal No.

G35-6 (BLW) - G35-4 (GND)

Tool Setting

2 V/DIV., 1 ms./DIV.

Condition
  • Engine switch on (IG)
  • Blower speed: LO

OK:

Waveform is similar to that shown in the illustration.

HINT:

The waveform varies with the blower speed.

OK

REPLACE BLOWER MOTOR WITH FAN SUB-ASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 2019 - 2020 MY Avalon Avalon HV [04/2018 - 08/2020]; HEATING / AIR CONDITIONING: AIR CONDITIONING AMPLIFIER: REMOVAL 2021 - 2022 MY Avalon Avalon HV [08/2020 -        ]; HEATING / AIR CONDITIONING: AIR CONDITIONING AMPLIFIER: REMOVAL