| Last Modified: 11-29-2007 | 1.6 J | |
| Service Category: Vehicle Interior | Section: Heating/Air Conditioning | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000002VXN004X |
| Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
Blower Motor Circuit |
DESCRIPTION
The blower motor is operated by signals from the air conditioning amplifier. Blower motor speed signals are transmitted by changes in the duty ratio.
Duty Ratio:
The duty ratio is the ratio of the blower motor OFF time (B) to the total of the blower motor ON and OFF time (A + B).
The blower motor controller controls the blower motor speed.
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
|
1. |
PERFORM ACTIVE TEST USING TECHSTREAM (BLOWER MOTOR) |
(a) Connect the Techstream to DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test/ Blower Motor
(e) According to the display on the Techstream, check blower motor operation while performing the Active Test.
Air Conditioner
|
Tester Display |
Test Part |
Control Range |
Diagnostic Note |
|---|---|---|---|
|
Blower Motor |
Blower motor |
Min.: 0, Max.: 31 |
- |
Result
|
Result |
Proceed to |
|---|---|
|
NG (blower motor does not operate) |
A |
|
NG (blower motor operates but does not change speed) |
B |
|
OK |
C |
|
|
3. |
INSPECT FUSE (HTR) |
|
(a) Remove the HTR fuse from the engine room relay block. |
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
HTR fuse |
Always |
Below 1 Ω |
(c) Reinstall the HTR fuse.
|
|
5. |
CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY AND BODY GROUND) |
(a) Disconnect the H41 blower motor connector.
(b) Measure the resistance and voltage according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
H41-3 (GND) - Body ground |
Always |
Below 1 Ω |
Standard Voltage:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
H41-1 (+B) - Body ground |
Always |
11 to 14 V |
(c) Reconnect the blower motor connector.
|
|
7. |
CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BLOWER MOTOR) |
(a) Disconnect the H24 air conditioning amplifier connector.
(b) Disconnect the H41 blower motor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
H24-23 (BLW) - H41-2 (S1) |
Always |
Below 1 Ω |
|
H24-23 (BLW) or H41-2 (S1) - Body ground |
Always |
10 kΩ or higher |
(d) Reconnect the blower motor connector.
(e) Reconnect the air conditioning amplifier connector.
|
|
9. |
CHECK BLOWER MOTOR (S1 VOLTAGE) |
(a) Disconnect the H24 air conditioning amplifier connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
|
Tester Connection |
Switch Condition |
Specified Condition |
|---|---|---|
|
H24-23 (BLW) - Body ground |
Ignition switch ON |
4.5 to 5.5 V |
(c) Reconnect the air conditioning amplifier connector.
|
|
11. |
INSPECT AIR CONDITIONING AMPLIFIER (BLW VOLTAGE) |
(a) Remove the air conditioning amplifier with its connectors still connected
.
(b) Turn the ignition switch to ON.
(c) Turn the blower switch to LO.
(d) Using an oscilloscope, check the waveform.
Blower Motor Control Signal
|
Terminal Name |
BLW - GND |
|
Tester Range |
1 V/DIV, 500 μsec./DIV |
|
Condition |
Ignition switch ON Blower switch LO |
HINT:
Waveform varies with the blower level.
(e) Reinstall the air conditioning amplifier.
|
|
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