CLIMATE CONTROL UNIT INSPECTION

id074000802200

1. Disconnect the negative battery cable. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION.)

2. Remove the following parts:

(1) Upper panel (See UPPER PANEL REMOVAL/INSTALLATION.)

(2) Rear console (See REAR CONSOLE REMOVAL/INSTALLATION.)

(3) Console side panel (See CONSOLE SIDE PANEL REMOVAL/INSTALLATION.)

(4) Shift lever knob (MTX) (See MANUAL TRANSAXLE SHIFT MECHANISM REMOVAL/INSTALLATION [C66M-R].)

(5) Selector lever knob (ATX) (See AUTOMATIC TRANSAXLE SHIFT MECHANISM REMOVAL/INSTALLATION.)

(6) Shift panel (See SHIFT PANEL REMOVAL/INSTALLATION.)

(7) Front console box (See FRONT CONSOLE BOX REMOVAL/INSTALLATION.)

(8) CD player

(9) Side wall (See SIDE WALL REMOVAL/INSTALLATION.)

(10) Front console

(11) Upper column cover (See COLUMN COVER REMOVAL/INSTALLATION.)

(12) Meter hood (See METER HOOD REMOVAL/INSTALLATION.)

(13) Glove compartment (See GLOVE COMPARTMENT REMOVAL/INSTALLATION.)

(14) Passenger-side decoration panel (See DECORATION PANEL REMOVAL/INSTALLATION.)

3. Remove the climate control unit with the connector connected. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)

4. Connect the negative battery cable.

5. Switch the ignition ON (engine off or on).

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

7. Insert the positive (+) lead of the tester into each climate control unit terminal and 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 (except for terminal 1W), replace the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)

― For terminal 1W, first try replacing the blower fan controller. (See BLOWER FAN CONTROLLER REMOVAL/INSTALLATION.)

If there is still malfunction, replace the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)

Terminal Voltage Table (Reference)

am6xuw00008430

Terminal

Signal name

Connected to

Measurement condition

Voltage (V)

Inspection item (s)

1A

Sensor GND

•  Air intake actuator

•  Driver-side air mix actuator

•  Passenger-side air mix actuator

•  Airflow mode actuator

•  Evaporator temperature sensor

•  Cabin temperature sensor

Under any condition

1.0 or less

•  Related wiring harness

•  Climate control unit: terminal voltage (1U)

1B

Solar radiation sensor (LH) input

Solar radiation sensor

Sunlight shined directly on solar radiation sensor

4

•  Related wiring harness

•  Climate control unit: terminal voltage (1U)

•  Solar radiation sensor

Blocking light to solar radiation sensor

1.0 or less

1C

MS_CAN_H

CAN related module

Because this terminal is for communication, integrity determination by terminal voltage is not possible.

•  Related wiring harness

1D

Potentiometer input

Air intake actuator

RECIRCULATE

1.0

•  Related wiring harness

•  Air intake actuator

FRESH

3.9

1E

MS_CAN_L

CAN related module

Because this terminal is for communication, integrity determination by terminal voltage is not possible.

•  Related wiring harness

1F

Potentiometer input

Airflow mode actuator

VENT

4.3

•  Related wiring harness

•  Airflow mode actuator

•  Climate control unit: terminal voltage (1U)

BI-LEVEL

3.4

HEAT

2.5

HEAT/DEF

1.6

DEFROSTER

0.7

1G

GND

Body ground

Under any condition

1.0 or less

•  Related wiring harness

1H

Potentiometer input

•  Passenger-side air mix actuator (L.H.D.)

•  Driver-side air mix actuator (R.H.D.)

Set temperature at MAX HOT

4.3

•  Related wiring harness

•  Passenger-side air mix actuator (L.H.D.)

•  Driver-side air mix actuator (R.H.D.)

•  Climate control unit: terminal voltage (1U)

Set temperature at MAX COLD

1.0

1I

Front seat warmer switch signal

Because this terminal is for communication, determination using terminal voltage inspection is not possible.

1J

Potentiometer input

•  Driver-side air mix actuator (L.H.D.)

•  Passenger-side air mix actuator (R.H.D.)

Set temperature at MAX HOT

4.3

•  Related wiring harness

•  Driver-side air mix actuator (L.H.D.)

•  Passenger-side air mix actuator (R.H.D.)

•  Climate control unit: terminal voltage (1U)

Set temperature at MAX COLD

1.0

1K

—

—

—

—

—

1L

—

—

—

—

—

1M

—

—

—

—

—

1N

Steering warmer indicator

Ignition switched ON (engine off)

Turn steering warmer switch on (steering warmer indicator turns on)

1.0 or less

•  Steering warmer control unit

Turn steering warmer switch off (steering warmer indicator turns off)

5

1O

Solar radiation sensor (RH) input

Solar radiation sensor

Sunlight shined directly on solar radiation sensor

4

•  Related wiring harness

•  Climate control unit: terminal voltage (1U)

•  Solar radiation sensor

Blocking light to solar radiation sensor

1.0 or less

1P

—

—

—

—

—

1Q

Cabin temperature sensor input

Cabin temperature sensor

Compared with temperature detected by cabin temperature sensor

Refer to graph 1

•  Related wiring harness

•  Cabin temperature sensor

•  Climate control unit: terminal voltage (1A)

1R

Steering warmer switch

Ignition switched ON (engine off)

Keep steering warmer switch push

B+

•  Steering warmer control unit

Release steering warmer switch

1.0 or less

1S

Evaporator temperature sensor input

Evaporator temperature sensor

Compared with temperature detected by evaporator temperature sensor

Refer to graph 2

•  Related wiring harness

•  Evaporator temperature sensor

•  Climate control unit: terminal voltage (1A)

1T

—

—

—

—

—

1U

+5V

•  Air intake actuator

•  Driver-side air mix actuator

•  Passenger-side air mix actuator

•  Airflow mode actuator

•  Solar radiation sensor

Under any condition

5

•  Related wiring harness

•  Air intake actuator

•  Driver-side air mix actuator

•  Passenger-side air mix actuator

•  Airflow mode actuator

•  Solar radiation sensor

•  Climate control unit: terminal voltage (1A)

1V

—

—

—

—

—

1W

Blower fan speed control

Blower fan controller

(See Blower Fan Speed Control Signal)

•  Related wiring harness

•  Blower fan controller

1X

IG2

Front body control module (FBCM)

Switch the ignition ON (engine off or on)

B+

•  Related wiring harness

•  Front body control module (FBCM)

Switch the ignition off

1.0 or less

2A

B+

ROOM 15 A fuse

Under any condition

B+

•  Related wiring harness

•  ROOM 15 A fuse

2B

Motor operation (FRESH)

Air intake actuator

Moving towards RECIRCULATE

1.0 or less

•  Related wiring harness

•  Air intake actuator

Moving towards FRESH

B+

2C

IG1

C/U IG1 15 A fuse

Switch the ignition ON (engine off or on)

B+

•  Related wiring harness

•  C/U IG1 15 A fuse

Switch the ignition off

1.0 or less

2D

Motor operation (RECIRCULATE)

Air intake actuator

Moving towards RECIRCULATE

B+

•  Related wiring harness

•  Air intake actuator

Moving towards FRESH

1.0 or less

2E

—

—

—

—

—

2F

Motor operation (COLD)

•  Driver-side air mix actuator (L.H.D.)

•  Passenger-side air mix actuator (R.H.D.)

Moving towards HOT

1.0 or less

•  Related wiring harness

•  Driver-side air mix actuator (L.H.D.)

•  Passenger-side air mix actuator (R.H.D.)

Moving towards COLD

B+

2G

—

—

—

—

—

2H

Motor operation (HOT)

•  Driver-side air mix actuator (L.H.D.)

•  Passenger-side air mix actuator (R.H.D.)

Moving towards HOT

B+

•  Related wiring harness

•  Driver-side air mix actuator (L.H.D.)

•  Passenger-side air mix actuator (R.H.D.)

Moving towards COLD

1.0 or less

2I

Motor operation (VENT)

Airflow mode actuator

Moving towards VENT

B+

•  Related wiring harness

•  Airflow mode actuator

Moving towards DEFROSTER

1.0 or less

2J

Motor operation (COLD)

•  Passenger-side air mix actuator (L.H.D.)

•  Driver-side air mix actuator (R.H.D.)

Moving towards HOT

1.0 or less

•  Related wiring harness

•  Passenger-side air mix actuator (L.H.D.)

•  Driver-side air mix actuator (R.H.D.)

Moving towards COLD

B+

2K

Motor operation (DEFROSTER)

Airflow mode actuator

Moving towards DEFROSTER

B+

•  Related wiring harness

•  Airflow mode actuator

Moving towards VENT

1.0 or less

2L

Motor operation (HOT)

•  Passenger-side air mix actuator (L.H.D.)

•  Driver-side air mix actuator (R.H.D.)

Moving towards HOT

B+

•  Related wiring harness

•  Passenger-side air mix actuator (L.H.D.)

•  Driver-side air mix actuator (R.H.D.)

Moving towards COLD

1.0 or less

Terminal	Signal name	Connected to	Measurement condition	Voltage (V)	Inspection item (s)
1A	Sensor GND	• Air intake actuator • Driver-side air mix actuator • Passenger-side air mix actuator • Airflow mode actuator • Evaporator temperature sensor • Cabin temperature sensor	Under any condition	1.0 or less	• Related wiring harness • Climate control unit: terminal voltage (1U)
1B	Solar radiation sensor (LH) input	Solar radiation sensor	Sunlight shined directly on solar radiation sensor	4	• Related wiring harness • Climate control unit: terminal voltage (1U) • Solar radiation sensor
Blocking light to solar radiation sensor	1.0 or less
1C	MS_CAN_H	CAN related module	Because this terminal is for communication, integrity determination by terminal voltage is not possible.	• Related wiring harness
1D	Potentiometer input	Air intake actuator	RECIRCULATE	1.0	• Related wiring harness • Air intake actuator
FRESH	3.9
1E	MS_CAN_L	CAN related module	Because this terminal is for communication, integrity determination by terminal voltage is not possible.	• Related wiring harness
1F	Potentiometer input	Airflow mode actuator	VENT	4.3	• Related wiring harness • Airflow mode actuator • Climate control unit: terminal voltage (1U)
BI-LEVEL	3.4
HEAT	2.5
HEAT/DEF	1.6
DEFROSTER	0.7
1G	GND	Body ground	Under any condition	1.0 or less	• Related wiring harness
1H	Potentiometer input	• Passenger-side air mix actuator (L.H.D.) • Driver-side air mix actuator (R.H.D.)	Set temperature at MAX HOT	4.3	• Related wiring harness • Passenger-side air mix actuator (L.H.D.) • Driver-side air mix actuator (R.H.D.) • Climate control unit: terminal voltage (1U)
Set temperature at MAX COLD	1.0
1I	Front seat warmer switch signal	Because this terminal is for communication, determination using terminal voltage inspection is not possible.
1J	Potentiometer input	• Driver-side air mix actuator (L.H.D.) • Passenger-side air mix actuator (R.H.D.)	Set temperature at MAX HOT	4.3	• Related wiring harness • Driver-side air mix actuator (L.H.D.) • Passenger-side air mix actuator (R.H.D.) • Climate control unit: terminal voltage (1U)
Set temperature at MAX COLD	1.0
1K	—	—	—	—	—
1L	—	—	—	—	—
1M	—	—	—	—	—
1N	Steering warmer indicator	Ignition switched ON (engine off)	Turn steering warmer switch on (steering warmer indicator turns on)	1.0 or less	• Steering warmer control unit
Turn steering warmer switch off (steering warmer indicator turns off)	5
1O	Solar radiation sensor (RH) input	Solar radiation sensor	Sunlight shined directly on solar radiation sensor	4	• Related wiring harness • Climate control unit: terminal voltage (1U) • Solar radiation sensor
Blocking light to solar radiation sensor	1.0 or less
1P	—	—	—	—	—
1Q	Cabin temperature sensor input	Cabin temperature sensor	Compared with temperature detected by cabin temperature sensor	Refer to graph 1	• Related wiring harness • Cabin temperature sensor • Climate control unit: terminal voltage (1A)
1R	Steering warmer switch	Ignition switched ON (engine off)	Keep steering warmer switch push	B+	• Steering warmer control unit
Release steering warmer switch	1.0 or less
1S	Evaporator temperature sensor input	Evaporator temperature sensor	Compared with temperature detected by evaporator temperature sensor	Refer to graph 2	• Related wiring harness • Evaporator temperature sensor • Climate control unit: terminal voltage (1A)
1T	—	—	—	—	—
1U	+5V	• Air intake actuator • Driver-side air mix actuator • Passenger-side air mix actuator • Airflow mode actuator • Solar radiation sensor	Under any condition	5	• Related wiring harness • Air intake actuator • Driver-side air mix actuator • Passenger-side air mix actuator • Airflow mode actuator • Solar radiation sensor • Climate control unit: terminal voltage (1A)
1V	—	—	—	—	—
1W	Blower fan speed control	Blower fan controller	(See Blower Fan Speed Control Signal)	• Related wiring harness • Blower fan controller
1X	IG2	Front body control module (FBCM)	Switch the ignition ON (engine off or on)	B+	• Related wiring harness • Front body control module (FBCM)
Switch the ignition off	1.0 or less
2A	B+	ROOM 15 A fuse	Under any condition	B+	• Related wiring harness • ROOM 15 A fuse
2B	Motor operation (FRESH)	Air intake actuator	Moving towards RECIRCULATE	1.0 or less	• Related wiring harness • Air intake actuator
Moving towards FRESH	B+
2C	IG1	C/U IG1 15 A fuse	Switch the ignition ON (engine off or on)	B+	• Related wiring harness • C/U IG1 15 A fuse
Switch the ignition off	1.0 or less
2D	Motor operation (RECIRCULATE)	Air intake actuator	Moving towards RECIRCULATE	B+	• Related wiring harness • Air intake actuator
Moving towards FRESH	1.0 or less
2E	—	—	—	—	—
2F	Motor operation (COLD)	• Driver-side air mix actuator (L.H.D.) • Passenger-side air mix actuator (R.H.D.)	Moving towards HOT	1.0 or less	• Related wiring harness • Driver-side air mix actuator (L.H.D.) • Passenger-side air mix actuator (R.H.D.)
Moving towards COLD	B+
2G	—	—	—	—	—
2H	Motor operation (HOT)	• Driver-side air mix actuator (L.H.D.) • Passenger-side air mix actuator (R.H.D.)	Moving towards HOT	B+	• Related wiring harness • Driver-side air mix actuator (L.H.D.) • Passenger-side air mix actuator (R.H.D.)
Moving towards COLD	1.0 or less
2I	Motor operation (VENT)	Airflow mode actuator	Moving towards VENT	B+	• Related wiring harness • Airflow mode actuator
Moving towards DEFROSTER	1.0 or less
2J	Motor operation (COLD)	• Passenger-side air mix actuator (L.H.D.) • Driver-side air mix actuator (R.H.D.)	Moving towards HOT	1.0 or less	• Related wiring harness • Passenger-side air mix actuator (L.H.D.) • Driver-side air mix actuator (R.H.D.)
Moving towards COLD	B+
2K	Motor operation (DEFROSTER)	Airflow mode actuator	Moving towards DEFROSTER	B+	• Related wiring harness • Airflow mode actuator
Moving towards VENT	1.0 or less
2L	Motor operation (HOT)	• Passenger-side air mix actuator (L.H.D.) • Driver-side air mix actuator (R.H.D.)	Moving towards HOT	B+	• Related wiring harness • Passenger-side air mix actuator (L.H.D.) • Driver-side air mix actuator (R.H.D.)
Moving towards COLD	1.0 or less

Blower Fan Speed Control Signal

Fan stopped

aaxjjw00019786

Climate control unit terminal

• 1W(+)—body ground(-)

Oscilloscope setting

• 5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition

• Switch the ignition ON (engine off or on)

Manual 1st

aaxjjw00019787

Climate control unit terminal

• 1W(+)—body ground(-)

Oscilloscope setting

• 5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition

• Switch the ignition ON (engine off or on)

• Airflow mode: VENT

• Air intake mode: RECIRCULATE

Manual 3rd

aaxjjw00019788

Climate control unit terminal

• 1W(+)—body ground(-)

Oscilloscope setting

• 5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition

• Switch the ignition ON (engine off or on)

• Airflow mode: VENT

• Air intake mode: RECIRCULATE

Manual 7th

aaxjjw00019789

Climate control unit terminal

• 1W(+)—body ground(-)

Oscilloscope setting

• 5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition

• Switch the ignition ON (engine off or on)

• Airflow mode: VENT

• Air intake mode: RECIRCULATE