The blower motor with fan sub-assembly is operated by signals from the air conditioning amplifier assembly. Blower motor speed signals are transmitted in accordance with changes in the duty ratio.
If the airflow volume is low or the blower speed cannot be changed, the following factors may be the cause.
| Symptom | Factor |
|---|---|
| Airflow volume cannot be changed | ·
Air conditioning amplifier assembly malfunction ·
Blower motor with fan sub-assembly malfunction ·
Harness or connector |
Inspect the fuses for circuits related to this system before performing the following procedure.
Perform the Active Test according to the display on the GTS.
| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Blower Level | Blower motor with fan sub-assembly | Min.: 0
Max.: 31 |
- |
| Tester Display |
|---|
| Blower Level |
| 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 |
A
B
Disconnect the A11 blower motor with fan sub-assembly connector.
| *a | Front view of wire harness connector
(to Blower Motor with Fan Sub-assembly) |
Measure the voltage and resistance according to the value(s) in the table below.
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| A11-3 (+B) - Body ground | Ignition switch off | 11 to 14 V |
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A11-1 (GND) - Body ground | Always | Below 1 Ω |
| Proceed to |
|---|
| OK |
| NG |
OK
NG
Disconnect the I49 air conditioning amplifier assembly connector.
Measure the resistance according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A11-2 (SI) - I49-21 (BLW) | Always | Below 1 Ω |
| A11-2 (SI) or I49-21 (BLW) - Other terminals and body ground | Always | 10 kΩ or higher |
| Proceed to |
|---|
| OK |
| NG |
OK
NG
| *a | Front view of wire harness connector
(to Air Conditioning Amplifier Assembly) |
Connect the A11 blower motor with fan sub-assembly connector.
Measure the voltage according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I49-21 (BLW) - Body ground | Always | 4.75 to 5.25 V |
| Proceed to |
|---|
| OK |
| NG |
OK
NG
| *a | Component with harness connected
(Air Conditioning Amplifier Assembly) |
Connect the I49 air conditioning amplifier assembly connector.
Turn the ignition switch to ON.
Set the blower speed to LO.
Using an oscilloscope, check the waveform.
| Item | Content |
|---|---|
| Terminal No. | I49-21 (BLW) - I49-17 (GND) |
| Tool Setting | 2 V/DIV., 1 ms./DIV. |
| Condition | ·
Ignition switch ON ·
Blower speed: LO |
Waveform is similar to that shown in the illustration.
The waveform varies with the blower speed.
| Proceed to |
|---|
| OK |
| NG |
OK
NG