Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000028C46
Model Year Start: 2023 Model: GR Corolla Prod Date Range: [11/2022 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System): Blower Motor Circuit; 2023 - 2025 MY Corolla Corolla Hatchback GR Corolla [11/2022 -        ]

Blower Motor Circuit

DESCRIPTION

The blower motor with fan sub-assembly is operated by signals from the air conditioning amplifier assembly.

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 GTS

(a) Perform the Active Test according to the display on the GTS.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Blower Level

This test activates the Blower Motor to adjust the air volume High/Low.

(Blower motor with fan sub-assembly)

0: Air Volume Low

31: Air Volume High

Operate with ignition switch ON.

Body Electrical > Air Conditioner > Active Test

Tester Display

Blower Level

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 - AUXILIARY BATTERY AND BODY GROUND)

(a) Disconnect the A11 blower motor with fan sub-assembly connector.

*a

Rear view of wire harness connector

(to Blower Motor with Fan Sub-assembly)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A11-1 (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

A11-3 (+B) - Body ground

Ignition switch off

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

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

(a) Disconnect the I49 air conditioning amplifier assembly connector.

(b) Disconnect the A11 blower motor with fan sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I49-21 (BLW) - A11-2 (SI)

Always

Below 1 Ω

I49-21 (BLW) or A11-2 (SI) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK BLOWER MOTOR WITH FAN SUB-ASSEMBLY

(a) Connect the A11 blower motor with fan sub-assembly connector.

(b) Disconnect the I49 air conditioning amplifier assembly connector.

*a

Front view of wire harness connector

(to Air Conditioning Amplifier Assembly)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

I49-21 (BLW) - Body ground

Always

4.75 to 5.25 V
NG

REPLACE BLOWER MOTOR WITH FAN SUB-ASSEMBLY

OK

5.

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Connect the I49 air conditioning amplifier assembly connector.

(b) Using an oscilloscope, check the waveform.

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)

-

-

Item

Content

Terminal No.

I49-21 (BLW) - I49-17 (GND)

Tool Setting

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

Condition
  • Ignition switch ON
  • Blower speed: LO

HINT:

The waveform varies with the blower speed.

OK:

Waveform is similar to that shown in the illustration.

OK

REPLACE BLOWER MOTOR WITH FAN SUB-ASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY