DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (FRONT BLOWER MOTOR)
CHECK HARNESS AND CONNECTOR (FRONT BLOWER MOTOR - BODY GROUND)
CHECK HARNESS AND CONNECTOR (FRONT BLOWER MOTOR - BATTERY)
CHECK FRONT BLOWER MOTOR (SI VOLTAGE)
CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - FRONT BLOWER MOTOR)
CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - FRONT BLOWER MOTOR)
CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (BLW SIGNAL)
AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System) - Blower Motor Circuit
DESCRIPTION
The blower motor is operated by signals from the air conditioning amplifier assembly. The blower motor speed signals are transmitted by changes in the duty ratio.
Duty Ratio:
The duty ratio is the ratio of the blower motor OPEN time (T1) to the total of the blower motor OPEN and LO time (T2).
The blower motor controller controls the blower motor speed.
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (FRONT BLOWER MOTOR) |
Select the Active Test, use the intelligent tester to generate a control command, and then check that the front blower motor operates.
Air Conditioner| Tester Display | Test Part | Control Range | Diagnostic Note |
| Blower Motor | Front blower motor | Min.: 0, Max.: 31 | - |
Result| Result | Proceed to |
| Front blower motor operates normally | A |
| Front blower motor does not operate | B |
| Front 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 (FRONT BLOWER MOTOR - BODY GROUND) |
Disconnect the A29 motor connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| A29-1 (GND) - Body ground | Always | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 3.CHECK HARNESS AND CONNECTOR (FRONT BLOWER MOTOR - BATTERY) |
Disconnect the A29 motor connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Condition | Specified Condition |
| A29-3 (+B) - Body ground | Always | 11 to 14 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 4.CHECK FRONT BLOWER MOTOR (SI VOLTAGE) |
Disconnect the E36*1 or E81*2 amplifier connector.
Reconnect the A29 motor connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| A29-2 (SI) - Body ground | Engine switch on (IG) | 4.5 to 5.5 V |
| | REPLACE FRONT BLOWER MOTOR ()
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| 5.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - FRONT BLOWER MOTOR) |
w/ Rear Heater
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 |
| E36-3 (BLW) - E36-1 (GND) | Engine switch on (IG)
Blower switch off | 4.5 to 5.5 V |
w/o Rear Heater
Disconnect the E81 amplifier connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| E81-23 (BLW) - E81-1 (GND) | Engine switch on (IG)
Blower switch off | 4.5 to 5.5 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| OK | |
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| REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY ()
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| 6.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - FRONT BLOWER MOTOR) |
w/ Rear Heater
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 |
| E36-3 (BLW) - E36-1 (GND) | Engine switch on (IG)
Blower switch off | 4.5 to 5.5 V |
w/o Rear Heater
Disconnect the E81 amplifier connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| E81-23 (BLW) - E81-1 (GND) | Engine switch on (IG)
Blower switch off | 4.5 to 5.5 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 7.CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (BLW SIGNAL) |
w/ Rear Heater
Remove the air conditioning amplifier assembly with its connectors still connected ().
Using an oscilloscope, check the waveform.
Measurement Condition| Item | Content |
| Terminal No. (Symbol) | E36-3 (BLW) - E36-1 (GND) |
| Tool Setting | 1 V/DIV., 500 μsec./DIV. |
| Condition | Engine switch on (IG)
Blower switch: off → on |
- OK:
- Waveform is as shown in the illustration.
- Waveform varies with the blower level.
w/o Rear Heater
Remove the air conditioning amplifier assembly with its connectors still connected ().
Using an oscilloscope, check the waveform.
Measurement Condition| Item | Content |
| Terminal No. (Symbol) | E81-23 (BLW) - E81-1 (GND) |
| Tool Setting | 1 V/DIV., 500 μsec./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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| OK | |
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| REPLACE FRONT BLOWER MOTOR ()
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