DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (REAR BLOWER MOTOR)
CHECK HARNESS AND CONNECTOR (WIRING AIR CONDITIONING HARNESS - BODY GROUND)
CHECK HARNESS AND CONNECTOR (WIRING AIR CONDITIONING HARNESS - BATTERY)
CHECK WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY (SI VOLTAGE)
CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - WIRING AIR CONDITIONING HARNESS)
CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (BLWH SIGNAL)
CHECK WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY (OPERATION)
INSPECT REAR BLOWER MOTOR
AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System) - Rear Blower Motor Circuit
DESCRIPTION
The rear blower motor (w/ rear heater) is operated by signals from the air conditioning amplifier assembly. The rear blower motor speed signals are transmitted by changes in the duty ratio.
Duty Ratio:
The duty ratio is the ratio of the rear blower motor OPEN time (T1) to the total of the rear blower motor OPEN and LO time (T2).
The rear blower motor controller controls the rear blower motor speed.
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (REAR BLOWER MOTOR) |
Select the Active Test, use the intelligent tester to generate a control command, and then check that the rear blower motor operates.
Air Conditioner| Tester Display | Test Part | Control Range | Diagnostic Note |
| Rear Blower Motor | Rear blower motor | Min.: 0, Max.: 31 | - |
Result| Result | Proceed to |
| Rear blower motor operates normally | A |
| Rear blower motor does not operate | B |
| Rear blower motor operates but does not change speed | C |
| A | |
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| PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE ()
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| 2.CHECK HARNESS AND CONNECTOR (WIRING AIR CONDITIONING HARNESS - BODY GROUND) |
Disconnect the wiring air conditioning harness sub-assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| 4 (GND) - Body ground | Always | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 3.CHECK HARNESS AND CONNECTOR (WIRING AIR CONDITIONING HARNESS - BATTERY) |
Disconnect the wiring air conditioning harness sub-assembly connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Condition | Specified Condition |
| 1 (+B) - Body ground | Always | 11 to 14 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 4.CHECK WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY (SI VOLTAGE) |
Disconnect the E36 amplifier connector.
Reconnect the wiring air conditioning harness sub-assembly connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| 8 (SI) - Body ground | Engine switch on (IG) | 4.5 to 5.5 V |
| 5.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - WIRING AIR CONDITIONING HARNESS) |
Disconnect the E36 amplifier connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| E36-17 (BLWH) - E36-1 (GND) | Engine switch on (IG)
Blower switch off | 4.5 to 5.5 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 6.CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (BLWH SIGNAL) |
Remove the air conditioning amplifier assembly with its connectors still connected ().
Using an oscilloscope, check the waveform.
Measurement Condition| Item | Content |
| Terminal No.(Symbol) | E36-17 (BLWH) - E36-1 (GND) |
| Tool Setting | 1 V/DIV., 500 μs/DIV. |
| Condition | Engine switch on (IG)
Blower switch: off → on |
- OK:
- Waveform is as shown in the illustration.
- Waveform varies with the blower level.
| | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY ()
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| 7.CHECK WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY (OPERATION) |
Replace the wiring air conditioning harness sub-assembly with a normal one and check that the condition returns to normal.
- OK:
- Same problem does not occur.
| OK | |
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| REPLACE WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY |
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| 8.INSPECT REAR BLOWER MOTOR |
Disconnect the z32 motor connector.
Connect the positive (+) lead of the battery to terminal 2 and the negative (-) lead to terminal 1, then check that the rear blower motor operates smoothly.
- OK:
- The rear blower motor operates smoothly.
| | REPLACE REAR BLOWER MOTOR ()
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| OK | |
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| REPLACE REAR BLOWER MOTOR CONTROLLER ()
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