Toyota 4Runner manuals

Toyota 4Runner: Blower Motor Circuit

DESCRIPTION


The blower with fan motor sub-assembly operates according to signals from the air conditioning amplifier assembly. The blower with fan motor sub-assembly speed signals are transmitted by changes in the duty ratio.

Duty Ratio:

The duty ratio is the ratio of the blower with fan motor sub-assembly on time (T1) to the total of the blower with fan motor sub-assembly on and off time (T2).

The air conditioning amplifier assembly controls the blower with fan motor sub-assembly speed.


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 (BLOWER WITH FAN MOTOR)

(a) Select the Active Test, use the Techstream to generate a control command, and then check that the blower with fan motor sub-assembly operates (See page ).


Air Conditioner

Tester Display

Test Part

Control Range

Diagnostic Note

Blower Motor

Blower with fan motor sub-assembly

Min.: 0, Max.: 31

-

OK:

Blower with fan motor sub-assembly operates and blower motor speed changes.


OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE


NG

2.

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

(a) Disconnect the F43 motor connector.


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

Standard Voltage:

Tester Connection

Condition

Specified Condition

F43-3 (+B) - Body ground

Always

11 to 14 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F43-1 (GND) - Body ground

Always

Below 1 Ω

Text in Illustration

*a

Front view of wire harness connector

(to Blower with Fan Motor Sub-assembly)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

3.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BLOWER WITH FAN MOTOR AND BODY GROUND)

(a) Disconnect the F42 amplifier connector.

(b) Disconnect the F43 motor connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F42-23 (BLW) - F43-2 (SI)

Always

Below 1 Ω

F42-23 (BLW) - Body ground

Always

10 kΩ or higher

F42-14 (GND) - Body ground

Always

Below 1 Ω


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

4.

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (BLW SIGNAL)

(a) Remove the air conditioning amplifier assembly with its connectors still connected (See page ).



(b) Using an oscilloscope, check the waveform.

Measurement Condition

Item

Content

Terminal No. (Symbol)

F42-23 (BLW) - F42-14 (GND)

Tool Setting

1 V/DIV., 500 μs/DIV.

Condition

Ignition switch ON

Blower switch LO

OK:

Waveform is as shown in the illustration.

Text in Illustration

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)

HINT:

Waveform varies with the blower level.


NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY


OK

5.

REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY

(a) Replace the blower with fan motor sub-assembly with a new or normally functioning one (See page ).


(b) Operate the blower with fan motor sub-assembly to check that it functions properly.

OK:

Blower with fan motor sub-assembly operates normally.


OK

END (BLOWER WITH FAN MOTOR SUB-ASSEMBLY IS FAULTY)


NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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