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
.gif)
).
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 | .gif) |
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
.gif)
|
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 |
|
*a |
Front view of wire harness connector (to Blower with Fan Motor Sub-assembly) |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
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 |
|
|
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 |
|
|
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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