Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000ZPDA
Model Year Start: 2017 Model: Sienna Prod Date Range: [08/2016 -           ]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: Blower Motor Circuit; 2017 - 2020 MY Sienna [08/2016 -        ]

Blower Motor Circuit

DESCRIPTION

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

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM

(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) Check the operation by referring to the table below.

Air Conditioner

Tester Display

Measurement Item

Control Range

Diagnostic Note

Blower Motor Speed Level

Blower motor with fan sub-assembly

Min.: 0

Max.: 31

-

OK:

Blower motor operates and blower motor speed level changes.

Result

Result

Proceed to

OK

A

NG (Blower motor does not operate)

B

NG (Blower motor operates but does not change speed)

C
A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

C

GO TO STEP 6

B

2.

CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND)

(a) Disconnect the blower motor connector.

*a

Front view of wire harness connector

(to Blower Motor)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D79-3 (GND) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY)

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

D79-1 (+B) - Body ground

Always

11 to 14 V

*a

Front view of wire harness connector

(to Blower Motor)
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

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

(a) Disconnect the D75 air conditioning amplifier connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D75-22 (BLW) - D79-2 (SI)

Always

Below 1 Ω

D75-22 (BLW) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

INSPECT BLOWER W/FAN MOTOR SUB-ASSEMBLY

(a) Reconnect the blower motor connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

D75-22 (BLW) - Body ground

Always

4.5 to 5.5 V

*a

Rear view of wire harness connector

(to Air Conditioning Amplifier)
NG

REPLACE BLOWER W/FAN MOTOR SUB-ASSEMBLY

OK

6.

INSPECT AIR CONDITIONING AMPLIFIER

(a) Remove the air conditioning amplifier.

*a

Component with harness connected

(Air Conditioning Amplifier)

(b) Reconnect the air conditioning amplifier connector.

(c) Turn the ignition switch to ON.

(d) Turn the blower switch LO.

(e) Measure the waveform between terminal D75-23 (BLW) of the air conditioning amplifier and body ground.

Item

Content

Tool setting

1 V/DIV., 500 μs/DIV.

Vehicle condition

Ignition switch ON

Blower switch LO

OK:

Waveform is as shown in the illustration.

HINT:

The waveform varies with the blower speed.

OK

REPLACE BLOWER W/FAN MOTOR SUB-ASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY