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

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

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

Result:

See step 5

Result:

See step 2

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

Disconnect the B14 blower motor with fan sub-assembly connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Rear view of wire harness connector (to Blower Motor with Fan Sub-assembly)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
B14-1 (GND) - Body ground	Always	Below 1 Ω

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

Standard Voltage

Tester Connection	Condition	Specified Condition
B14-3 (+B) - Body ground	Ignition switch off	11 to 14 V

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 3

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

Disconnect the D34 air conditioning amplifier assembly connector.
Disconnect the B14 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
D34-21 (BLW) - B14-2 (SI)	Always	Below 1 Ω
D34-21 (BLW) or B14-2 (SI) - 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 4

CHECK BLOWER MOTOR WITH FAN SUB-ASSEMBLY

Connect the B14 blower motor with fan sub-assembly connector.

Disconnect the D34 air conditioning amplifier assembly connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Front view of wire harness connector (to Air Conditioning Amplifier Assembly)

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

Standard Voltage

Tester Connection	Condition	Specified Condition
D34-21 (BLW) - Body ground	Always	4.75 to 5.25 V

Result

Proceed to
OK
NG

Result:

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

Result:

See step 5

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

Connect the D34 air conditioning amplifier assembly connector.

Using an oscilloscope, check the waveform.

Component with harness connected
(Air Conditioning Amplifier Assembly)

Item	Content
Terminal No.	D34-21 (BLW) - D34-17 (GND)
Tool Setting	2 V/DIV., 1 ms./DIV.
Condition	Ignition switch ON Blower speed: LO

HINT:

The waveform varies with the blower speed.

Waveform is similar to that shown in the illustration.

Result

Proceed to
OK
NG

Result:

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

Result:

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