Last Modified: 01-30-2024 6.11:8.1.0 Doc ID: RM100000001FPEK
Model Year Start: 2019 Model: RAV4 Prod Date Range: [11/2018 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model): Blower Motor Circuit; 2019 - 2024 MY RAV4 [11/2018 -        ]

Blower Motor Circuit

DESCRIPTION

The blower with fan motor sub-assembly reads the signal from the air conditioning amplifier assembly and controls operation and speed changes of the blower motor.

If the blower air volume is weak, or there are any other blower malfunctions such as the temperature or air volume cannot be changed, the following causes are possible.

Malfunction Status

Factor
  • Blower airflow volume is weak
  • Blower airflow volume cannot be changed
  • Air conditioning amplifier assembly malfunction
  • Blower with fan motor sub-assembly malfunction
  • Air conditioning control assembly malfunction
  • Evaporator or heater core fin clogging
  • Clean air filter clogging

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 (BLOWER MOTOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(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 with fan motor sub-assembly

Min.: 0

Max.: 31

-

Body Electrical > Air Conditioner > Active Test

Tester Display

Blower Motor

OK:

Blower with fan motor sub-assembly is operated.

NG

GO TO STEP 5

OK

2.

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

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

*a

Rear view of wire harness connector

(to Blower with Fan Motor Sub-assembly)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A21-1 (GND) - Body ground

Always

Below 1 Ω

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A21-3 (+B) - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

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

(a) Disconnect the G46 air conditioning amplifier assembly connector.

(b) Disconnect the A21 blower with fan motor sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G46-21 (BLW) - A21-2 (SI)

Always

Below 1 Ω

G46-21 (BLW) or A21-2 (SI) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK BLOWER WITH FAN MOTOR SUB-ASSEMBLY

(a) Disconnect the air conditioning amplifier assembly connector.

*a

Front view of wire harness connector

(to Air Conditioning Amplifier Assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

G46-21 (BLW) - Body ground

Always

4.75 to 5.25 V
NG

REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY

OK

5.

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Using the oscilloscope, check for the waveform.

Item

Content

Terminal No.

A21-2 (SI) - Body ground

Tool Setting

1 V/DIV., 500 μs./DIV.

Vehicle Condition
  • Ignition switch ON
  • Blower switch: LO

HINT:

The waveform varies with the blower speed.

OK:

Waveform is similar to that shown in the illustration.

*a

Component with harness connected

(Blower with Fan Motor Sub-assembly)
OK

REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY