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)

-