FRONT CLIMATE CONTROL UNIT INSPECTION

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1. Connect the front climate control unit connector.

2. Turn the ignition switch to the ON position.

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

4. By inserting the positive (+) lead of the tester into each front climate control unit 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 front climate control unit.

Terminal Voltage Table (Reference)

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Terminal | Signal name | Connected to | Measurement condition | Voltage (V) | Inspection item (s)
--- | --- | --- | --- | --- | ---
1A | Motor operation | Driver-side front air mix actuator | Temperature control dial (driver side): Moving towards COLD | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—driver-side front air mix actuator: 1A—G, 1D—F) • Driver-side front air mix actuator
Temperature control dial (driver side): Moving towards HOT | B+
1B | B+ | ROOM 15 A fuse | Under any condition | B+ | • Wiring harness: continuity, short circuit (Front climate control unit— ROOM 15 A fuse) • ROOM 15 A fuse
1C | Motor operation | Passenger-side front air mix actuator | Temperature control dial (passenger side): Moving towards COLD*1 Moving towards HOT*2 | B+ | • Wiring harness: continuity, short circuit (Front climate control unit—passenger-side front air mix actuator: 1C—G, 1E—F) • Passenger-side front air mix actuator
Temperature control dial (passenger side): Moving towards HOT*1 Moving towards COLD*2 | 1.0 or less
1D | Motor operation | Driver-side front air mix actuator | Temperature control dial (driver side): Moving towards COLD | B+ | • Wiring harness: continuity, short circuit (Front climate control unit—driver-side front air mix actuator: 1A—G, 1D—F) • Driver-side front air mix actuator
Temperature control dial (driver-side): Moving towards HOT | 1.0 or less
1E | Motor operation | Passenger-side front air mix actuator | Temperature control dial (passenger side): Moving towards COLD*1 Moving towards HOT*2 | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—passenger-side front air mix actuator: 1C—G, 1E—F) • Passenger-side front air mix actuator
Temperature control dial (passenger side): Moving towards HOT*1 Moving towards COLD*2 | B+
1F | Motor operation | Front airflow mode actuator | Defroster switch on | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—front airflow mode actuator: 1F—G, 1H—F) • Front airflow mode actuator
Mode switch: Moving towards VENT | B+
1G | Motor operation | Rear air mix actuator | Temperature control dial (rear side): Moving towards COLD | B+ | • Wiring harness: continuity, short circuit (Front climate control unit—Rear air mix actuator: 1G—F, 1I—G) • Rear air mix actuator
Temperature control dial (rear side): Moving towards HOT | 1.0 or less
1H | Motor operation | Front airflow mode actuator | Defroster switch on: Moving towards DEFROSTER | B+ | • Wiring harness: continuity, short circuit (Front climate control unit—front airflow mode actuator: 1F—G, 1H—F) • Front airflow mode actuator
Mode switch: Moving towards VENT | 1.0 or less
1I | Motor operation | Rear air mix actuator | Temperature control dial (rear side): Moving towards COLD | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—Rear air mix actuator: 1G—F, 1I—G) • Rear air mix actuator
Temperature control dial (rear side): Moving towards HOT | B+
1J | Motor operation | Rear airflow mode actuator | Airflow mode switch (rear side): Moving towards VENT | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—Rear airflow mode actuator: 1J—G, 1L—F) • Rear airflow mode actuator
Airflow mode switch (rear side): Moving towards HEAT | B+
1K | Motor operation | Air intake actuator | REC switch: Switched to RECIRCULATE*1 Switched to FRESH*2 | B+ | • Wiring harness: continuity, short circuit (Front climate control unit—air intake actuator: 1K—A, 1M—C) • Air intake actuator
REC switch: Switched to FRESH*1 Switched to RECIRCULATE*2 | 1.0 or less
1L | Motor operation | Rear airflow mode actuator | Airflow mode switch (rear side): Moving towards HEAT | B+ | • Wiring harness: continuity, short circuit (Front climate control unit—Rear airflow mode actuator: 1J—G, 1L—F) • Rear airflow mode actuator
Airflow mode switch (rear side): Moving towards VENT | 1.0 or less
1M | Motor operation | Air intake actuator | REC switch: Switched to RECIRCULATE*1 Switched to FRESH*2 | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—air intake actuator: 1K—A, 1M—C) • Air intake actuator
REC switch: Switched to FRESH*1 Switched to RECIRCULATE*2 | B+
1N | Front blower motor feedback | Front power MOS FET | Airflow volume control dial | Off | Approx. 7.3 | 1. Wiring harness: continuity, short circuit (Front climate control unit—front power MOS FET: 1N—C, 1P—A) 2. Wiring harness: continuity (Front power MOS FET—body ground: D—ground) 3. Front power MOS FET 4. Front blower motor 5. Front blower relay 6. HEATER 50 A fuse
1st. | Approx. 5.4
2nd. | Approx. 4.6
3rd. | Approx. 3.7
4th. | Approx. 2.9
5th. | Approx. 2.0
6th. | Approx. 1.1
7th. | 1.0 or less
1O | Rear window defroster switch | Rear window defroster relay | Rear window defroster switch on | 1.0 or less | • Front climate control unit: terminal voltage (1X)
Rear window defroster switch off | B+ | • Wiring harness: open circuit, short circuit (Front climate control unit—rear window defroster relay (main fuse block): 1O—A) • Rear window defroster relay
1P | Front blower fan speed control | Front power MOS FET | Airflow volume control dial | Off | 1.0 or less | • Front climate control unit: terminal voltage (1N)
1st. | Approx. 2.1
2nd. | Approx. 2.2
3rd. | Approx. 2.3
4th. | Approx. 2.4
5th. | Approx. 2.5
6th. | Approx. 2.7
7th. | Approx. 10.7
1Q | — | — | — | — | —
1R | Rear blower motor feedback | Rear power MOS FET | Rear airflow volume control dial | Off | Approx. 8.5 | 1. Wiring harness: continuity, short circuit (Front climate control unit—rear power MOS FET: 1R—D, 1T—C) 2. Wiring harness: continuity (Rear power MOS FET—body ground: A—ground) 3. Rear power MOS FET 4. Rear blower motor 5. Rear blower relay 6. R.HEATER 40 A fuse
1st. | Approx. 6.1
2nd. | Approx. 4.8
3rd. | Approx. 3.6
4th. | Approx. 1.9
5th. | 1.0 or less
1S | Seat warmer (RH) | Seat warmer controller | Seat warmer switch off | B+ | • Related wiring harness • Seat warmer controller
Seat warmer switch 1st | Approx. 2.7
Seat warmer switch 2nd | Approx. 1.7
1T | Rear blower fan speed control | Rear power MOS FET | Rear airflow volume control dial | Off | 1.0 or less | • Front climate control unit: terminal voltage (1R)
1st. | Approx. 2.1
2nd. | Approx. 2.2
3rd. | Approx. 2.2
4th. | Approx. 2.3
5th. | Approx. 2.4
1U | Seat warmer (LH) | Seat warmer controller | Seat warmer switch off | B+ | • Related wiring harness • Seat warmer controller
Seat warmer switch 1st | Approx. 2.7
Seat warmer switch 2nd | Approx. 1.7
1V | — | — | — | — | —
1W | IG2 | A/C 7.5 A fuse | Ignition switch is at ON position | B+ | • Wiring harness: continuity, short circuit (Front climate control unit— fuse: 1W—A/C 7.5 A) • A/C 7.5 A fuse
Ignition switch is at OFF position | 1.0 or less
1X | Ground | Body ground | Under any condition: Inspect for continuity to ground | 1.0 or less | • Wiring harness: continuity (Front climate control unit—ground: 1X—ground)
2A | ECT sensor signal | Instrument cluster | Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. | —
2B | +5 V | • Driver-side front air mix actuator • Passenger-side front air mix actuator • Front airflow mode actuator • Solar radiation sensor • Rear air mix actuator • Rear airflow mode actuator | Under any condition | 5.0 | • Wiring harness: short circuit (Front climate control unit—driver-side front air mix actuator, passenger-side front air mix actuator, front airflow mode actuator, solar radiation sensor, rear air mix actuator, rear airflow mode actuator: 2B—A, A, A, A, A, C) • Driver-side front air mix actuator • Passenger-side front air mix actuator • Front airflow mode actuator • Solar radiation sensor • Rear air mix actuator • Rear airflow mode actuator
2C | Information display signal | Information display | Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. | —
2D | Potentiometer input | Rear airflow mode actuator | Airflow mode switch(rear side): Moving towards VENT | Approx. 0.5 | • Wiring harness: continuity, short circuit (Front climate control unit—rear airflow mode actuator: 2D—E) • Rear airflow mode actuator • Front climate control unit: terminal voltage (2B)
Airflow mode switch (rear side): Moving towards BI-LEVEL | Approx. 2.4
Airflow mode switch(rear side): Moving towards HEAT | Approx. 4.3
2E | Potentiometer input | Front airflow mode actuator | Mode switch: Moving towards VENT | Approx. 1.0 | • Wiring harness: continuity, short circuit (Front climate control unit—front airflow mode actuator: 2E—E) • Front airflow mode actuator • Front climate control unit: terminal voltage (2B)
Mode switch: Moving towards BI-LEVEL | Approx. 1.9
Mode switch: Moving towards HEAT | Approx. 2.5
Mode switch: Moving towards HEAT/DEF | Approx. 3.3
Defroster switch on | Approx. 4.0
2F | Potentiometer input | Driver-side front air mix actuator | Temperature control dial (driver side): Set temperature at MAX COLD | 4.0 | • Wiring harness: continuity, short circuit (Front climate control unit—driver-side front air mix actuator: 2F—E) • Driver-side front air mix actuator • Front climate control unit: terminal voltage (2B)
Temperature control dial (driver side): Set temperature at MAX HOT | 1.0
2G | Potentiometer input | Passenger-side front air mix actuator | Temperature control dial (passenger side): Set temperature at MAX COLD | 1.0 | • Wiring harness: continuity, short circuit (Front climate control unit—passenger-side front air mix actuator: 2G—E) • Passenger-side front air mix actuator • Front climate control unit: terminal voltage (2B)
Temperature control dial (passenger side): Set temperature at MAX HOT | 4.0
2H | Front evaporator temperature sensor input | Front evaporator temperature sensor | Compared with temperature detected by front evaporator temperature sensor | Refer to graph 1 | • Wiring harness: continuity (Front climate control unit—front evaporator temperature sensor: 2H—B, 2P—A) • Wiring harness: short circuit (Front climate control unit—front evaporator temperature sensor: 2H—B) • Front evaporator temperature sensor
2I | Ambient temperature sensor input | Ambient temperature sensor | Compared with temperature detected by ambient temperature sensor | Refer to graph 2 | • Wiring harness: continuity (Front climate control unit—ambient temperature sensor: 2I—B, 2P—A) • Wiring harness: short circuit (Front climate control unit—ambient temperature sensor: 2I—B) • Ambient temperature sensor
2J | Rear evaporator temperature sensor input | Rear evaporator temperature sensor | Compared with temperature detected by rear evaporator temperature sensor | Refer to graph 3 | • Wiring harness: continuity (Front climate control unit—rear evaporator temperature sensor: 2J—B, 2P—A) • Wiring harness: short circuit (Front climate control unit—rear evaporator temperature sensor: 2J—B) • Rear evaporator temperature sensor
2K | Cabin temperature sensor input | Cabin temperature sensor | Compared with temperature detected by cabin temperature sensor | Refer to graph 4 | • Wiring harness: continuity (Front climate control unit—cabin temperature sensor: 2K—B, 2P—A) • Wiring harness: short circuit (Front climate control unit—cabin temperature sensor: 2K—B) • Cabin temperature sensor
2L | — | — | — | — | —
2M | Solar radiation sensor (LH) input | Solar radiation sensor | Natural sunlight shined directly on the solar radiation sensor | 4.0 | • Wiring harness: continuity (Front climate control unit—solar radiation sensor: 2M—C, 2B—A) • Front climate control unit: terminal voltage (2B) • Solar radiation sensor
Blocking light to solar radiation sensor | 1.0 or less
2N | Potentiometer input | Rear air mix actuator | Temperature control dial (rear side): Set temperature at MAX COLD | 1.3 | • Wiring harness: continuity, short circuit (Front climate control unit—rear air mix actuator: 2N—E) • Rear air mix actuator • Front climate control unit: terminal voltage (2B)
Temperature control dial (rear side): Set temperature at MAX HOT | 4.0
2O | Solar radiation sensor (RH) input | Solar radiation sensor | Natural sunlight shined directly on the solar radiation sensor | 4.0 | • Wiring harness: continuity (Front climate control unit—solar radiation sensor: 2O—B, 2B—A) • Front climate control unit: terminal voltage (2B) • Solar radiation sensor
Blocking light to solar radiation sensor | 1.0 or less
2P | Sensor ground | • Driver-side front air mix actuator • Passenger-side front air mix actuator • Front airflow mode actuator • Ambient temperature sensor • Cabin temperature sensor • Front evaporator temperature sensor • Rear air mix actuator • Rear airflow mode actuator • Rear evaporator temperature sensor | Under any condition: Inspect for continuity to ground | 1.0 or less | • Front climate control unit: terminal voltage (1X)
3A | — | — | — | — | —
3A*3 | Country destination recognize | Body ground | Under any condition: Inspect for continuity to ground | 1.0 or less | • Wiring harness: continuity (Front climate control unit—ground: 3A—ground)
3B | IG2 | Rear climate control unit | Ignition switch is at ON position | B+ | • Wiring harness: continuity, short circuit (Front climate control unit—rear climate control unit: 3B—B) • Front climate control unit: terminal voltage (1W, 1X)
Ignition switch is at OFF position | 1.0 or less
3C | Rear climate control unit communication | Rear climate control unit | Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. | —
3D | TNS signal | ILLUMI 10 A fuse | Turn the headlight switch to the off position | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—ILLUMI 10 A fuse) • TNS relay • Headlight switch
Turn the headlight switch to the TNS position | B+
3E | Rear climate control unit communication | Rear climate control unit | Because this terminal is for communication, good/no good judgment by terminal voltage is not possible. | —
3F | TNS signal | Rear climate control unit | Turn the headlight switch to the off position | 1.0 or less | • Wiring harness: continuity, short circuit (Front climate control unit—rear climate control unit: 3F—F) • ILLUMI 10 A fuse • TNS relay • Headlight switch
Turn the headlight switch to the TNS position | B+
3G | On-board diagnostic signal | Check connector | Check connector is shorted. | 1.0 or less | • Related wiring harness
3H | Panel light control | Rear climate control unit | Turn the headlight switch to the TNS position and panel light control switch at MIN | 6.76 | • Wiring harness: continuity, short circuit (Front climate control unit—rear climate control unit: 3H—H)
Turn the headlight switch to the TNS position and panel light control switch at MAX | 1.0 or less
3I | Ground | Rear climate control unit | Under any condition: Inspect for continuity to ground | 1.0 or less | • Wiring harness: continuity (Front climate control unit—rear climate control unit: 3I—I)
3J | Panel light control | Instrument cluster | Turn the headlight switch to the TNS position and panel light control switch at MIN | B+ | • Related wiring harness • Instrument cluster
Turn the headlight switch to the TNS position and panel light control switch at MAX | 1.0 or less
3K | — | — | — | — | —
3L | — | — | — | — | —

*1 :L.H.D.
*2 :R.H.D.
*3 :European (L.H.D.) specs.