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A/C AMPLIFIER INSPECTION [MANUAL AIR CONDITIONER]

BHE074061190W04

1. Turn the ignition switch to the ON position.

2. Connect the negative (-) lead of the tester to body ground.

3. By inserting the positive (+) lead of the tester into each A/C amplifier terminal, measure the voltage according to the terminal voltage table.

  • If there is any malfunction, inspect the parts under "Inspection item(s)".

  – If the parts under "Inspection item(s)" are found to be normal, replace the A/C amplifier.

## Terminal Voltage Table (Reference)

Terminal | Signal name | Connected to | Measured condition | Voltage (V) | Inspection item(s)
--- | --- | --- | --- | --- | ---
1A | - | - | - | - | -
1B | - | - | - | - | -
1C | - | - | - | - | -
1D | - | - | - | - | -
1E | Blower motor feedback | • Resistor • Fan switch | Fan stopped | B+ | 1. Wiring harness: continuity, short circuit (A/C amplifier-resistor, fan switch: 1E-D, C) (Blower motor-blower relay: A-C) (Blower relay-fuse: D-HEATER 40 A) 2. Resistor 3. Fan switch 4. Blower motor 5. Blower relay 6. HEATER 40 A fuse
Fan switch: 1st | 0.3
Fan switch: 2nd | 1.5
Fan switch: 3rd | 1.3
Fan switch: 4th | 0.7
1F | - | - | - | - | -
1G | - | - | - | - | -
1H | - | - | - | - | -
1I | Motor operation | Air intake actuator | Switched to RECIRCULATE | 1.0 or less | • Wiring harness: continuity, short circuit (A/C amplifier-air intake actuator: 1I-A, 1J-C) • Air intake actuator
Switched to FRESH | 12
1J | Motor operation | Air intake actuator | Switched to RECIRCULATE | 12 | • Wiring harness: continuity, short circuit (A/C amplifier-air intake actuator: 1J-C, 1I-A) • Air intake actuator
Switched to FRESH | 1.0 or less
1K | Rear window defroster operation | Rear window defroster relay | Rear window defroster switch OFF | B+ | • Wiring harness: continuity, short circuit (A/C amplifier-rear window defroster relay: 1K-E) • Rear window defroster relay
Rear window defroster switch ON | 1.0 or less | • A/C amplifier: terminal voltage (2C, 2N)
1L | - | - | - | - | -
1M | A/C | Refrigerant pressure switch | Fan stopped | B+ | • Wiring harness: continuity, short circuit (A/C amplifier-refrigerant pressure switch: 1M-B) (Refrigerant pressure switch -PCM: C -4W) • Refrigerant pressure switch • PCM: terminal voltage (4W)
Fan switch: ON and A/C switch: ON | 1.0 or less | • A/C amplifier: terminal voltage (2C, 2N)
1N | - | - | - | - | -
1O | - | - | - | - | -
1P | Signal | - | - | - | -
1Q | - | - | - | - | -
1R | Signal | - | - | - | -
1S | - | - | - | - | -
1T | - | - | - | - | -
1U | Motor operation | Air mix actuator | Moving towards COLD | 1.0 or less | • Wiring harness: continuity, short circuit (A/C amplifier-air mix actuator: 1U-F, 1V-G) • Air mix actuator
Moving towards HOT | 12
1V | Motor operation | Air mix actuator | Moving towards COLD | 12 | • Wiring harness: continuity, short circuit (A/C amplifier-air mix actuator: 1U-F, 1V-G) • Air mix actuator
Moving towards HOT | 1.0 or less
1W | Motor operation | Airflow mode actuator | Switched to DEFROSTER | 12 | • Wiring harness: continuity, short circuit (A/C amplifier-airflow mode actuator: 1W-G, 1X-F) • Airflow mode actuator
Switched to VENT | 1.0 or less
1X | Motor operation | Airflow mode actuator | Switched to DEFROSTER | 1.0 or less | • Wiring harness: continuity, short circuit (A/C amplifier-airflow mode actuator: 1W-G, 1X-F) • Airflow mode actuator
Switched to VENT | 12
2A | B+ | ROOM 15 A fuse | Under any condition | B+ | • Wiring harness: continuity, short circuit (A/C amplifier-fuse: 2F-ROOM 15 A) • ROOM 15 A fuse
2B | - | - | - | - | -
2C | IG2 | A/C 7.5 A fuse | IG SW ON | B+ | • Wiring harness: continuity, short circuit (A/C amplifier- fuse: 2C-A/C 7.5 A) • A/C 7.5 A fuse
IG SW LOCK | 1.0 or less | • Wiring harness: continuity, short circuit (A/C amplifier-fuse: 2C-A/C 7.5 A)
2D | - | - | - | - | -
2E | - | - | - | - | -
2F | - | - | - | - | -
2G | Potentiometer input | Airflow mode actuator | VENT | 4.0 | • Wiring harness: continuity, short circuit (A/C amplifier-airflow mode actuator: 2G-E, 2P-C) • Airflow mode actuator • A/C amplifier: terminal voltage (2O)
BI-LEVEL | 3.3
HEAT | 2.6
HEAT/DEF | 1.8
DEFROSTER | 1.0
2H | Potentiometer input | Air mix actuator | Set temperature at MAX COLD | 3.9 | • Wiring harness: continuity, short circuit (A/C amplifier-air mix actuator: 2H-E, 2P-A) • Air mix actuator • A/C amplifier: terminal voltage (2O)
Set temperature at MAX HOT | 1.1
2I | - | - | - | - | -
2J | Evaporator temperature sensor input | Evaporator temperature sensor | Compared with temperature detected by evaporator temperature sensor | Refer to graph 1 | • Wiring harness: continuity (A/C amplifier-evaporator temperature sensor: 2J-B, 2P-A) • Wiring harness: short circuit (A/C amplifier-evaporator temperature sensor: 2J-B) • Evaporator temperature sensor • A/C amplifier: terminal voltage (2C, 2N)
2K | Ambient temperature sensor input | Ambient temperature sensor | Compared with temperature detected by ambient temperature sensor | Refer to graph 2 | • Wiring harness: continuity (A/C amplifier-ambient temperature sensor: 2K-B, 2P-A) • Wiring harness: short circuit (A/C amplifier-ambient temperature sensor: 2K-B) • Ambient temperature sensor • A/C amplifier: terminal voltage (2C, 2N)
2L | - | - | - | - | -
2M | ECT sensor input | PCM | Compared with temperature detected by ECT sensor | Refer to graph 3 | • Wiring harness: continuity, short circuit (A/C amplifier-PCM: 2M-5W) • ECT sensor • A/C amplifier: terminal voltage (2C, 2N)
2N | GND | Body ground | Under any condition | 1.0 or less | • Wiring harness: continuity (A/C amplifier-GND: 2N-GND)
2O | +5 V | • Air mix actuator • Airflow mode actuator | IG SW ON | 5.0 | • Wiring harness: short circuit (A/C amplifier-air mix actuator, airflow mode actuator: 2O-C, A) • Air mix actuator • Airflow mode actuator • A/C amplifier: terminal voltage (2C, 2N)
IG SW LOCK | 1.0 or less | • A/C amplifier replacement
2P | Sensor GND | • Ambient temperature sensor • Evaporator temperature sensor • Air mix actuator • Airflow mode actuator | Under any condition | 1.0 or less | • A/C amplifier: terminal voltage (2N)

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