Rear Blower Motor Circuit [12/2023 - ]: Procedure

WARNING: This page is about a different car, the 2024 Lexus TX 550h+. However, it is still accessible from the selected car via links, so may be relevant.

PERFORM ACTIVE TEST USING GTS (REAR BLOWER MOTOR)

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
Rear Blower Level	This test activates the rear blower motor to adjust the air volume high/low. (Rear blower motor with fan sub-assembly)	0: Air Volume Low 31: Air Volume High	Operate with the ignition switch ON.

Body Electrical > Air Conditioner > Active Test

Tester Display
Rear Blower Level

Result

Result	Proceed to
Rear blower motor with fan sub-assembly does not operate	A
Rear blower motor with fan sub-assembly operates but does not change speed	B

Result:

See step 6

Result:

See step 2

CHECK HARNESS AND CONNECTOR (REAR BLOWER MOTOR CONTROL - POWER SOURCE AND BODY GROUND)

Disconnect the I10 rear blower motor control connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Front view of wire harness connector (to Rear Blower Motor Control)

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

Standard Voltage

Tester Connection	Condition	Specified Condition
I10-1 (+B) - Body ground	Ignition switch off	11 to 14 V

Standard Resistance

Tester Connection	Condition	Specified Condition
I10-6 (GND) - Body ground	Always	Below 1 Ω

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 3

INSPECT REAR BLOWER MOTOR WITH FAN SUB-ASSEMBLY
Refer to INSPECTION [09/2023 - ]

Result

Proceed to

OK

NG

Result:

NG

REPLACE REAR BLOWER MOTOR WITH FAN SUB-ASSEMBLY. Refer to REMOVAL [09/2023 - ]

Result:

OK

See step 4

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

Disconnect the I10 rear blower motor control connector.
Disconnect the I9 rear blower motor with fan sub-assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
I9-2 (+) - I10-2 (VM)	Always	Below 1 Ω
I9-1 (-) - Body ground	Always	Below 1 Ω
I9-2 (+) or I10-2 (VM) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 5

CHECK HARNESS AND CONNECTOR (REAR BLOWER MOTOR CONTROL - AIR CONDITIONING AMPLIFIER ASSEMBLY)

Disconnect the I10 rear blower motor control connector.
Disconnect the D36 air conditioning amplifier assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
I10-3 (SI) - D36-10 (SBLW)	Always	Below 1 Ω
I10-3 (SI) or D36-10 (SBLW) - Other terminals and body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 6

INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

Connect the I10 rear blower motor control connector.
Connect the I9 rear blower motor with fan sub-assembly connector.
Connect the D36 air conditioning amplifier assembly connector.

Using an oscilloscope, check the waveform.

Component with harness connected
(Air Conditioning Amplifier Assembly)

Item	Content
Terminal No.	D36-10 (SBLW) - D36-4 (GND2)
Tool Setting	2 V/DIV., 1 ms./DIV.
Condition	Ignition switch ON Blower speed: LO

Waveform is similar to that shown in the illustration.

HINT:

The waveform varies with the blower speed.

Result

Proceed to
OK
NG

Result:

REPLACE REAR BLOWER MOTOR CONTROL. Refer to REMOVAL [09/2023 - ]

Result:

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to REMOVAL [09/2023 - ]