Mazda CX 7. Manual - part 297

CONTROL SYSTEM 

07-40–13

07-40

CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER]

id074000803400

1. Remove the climate control unit. (See 07-40-25 CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-

AUTO AIR CONDITIONER].)

2. Install the audio unit. (See 09-20-4 AUDIO UNIT REMOVAL/INSTALLATION.)
3. Connect the climate control unit connector.
4. Connect the negative (-) lead of the tester to body ground.
5. Turn the ignition switch to the ON position.
6. By inserting the positive (+) lead of the tester into each 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 (except for terminal T), replace the 

climate control unit.

— For terminal T, first try replacing the power MOS FET. If there is still any malfunction, replace the 

climate control unit.

Terminal Voltage Table (Reference)

Term

inal

Signal 

name

Connected to

Measurement 

condition

Voltage (V)

Inspection item (s)

A

Communicat

ion

— — 

— 

— 

B

Communicat

ion

— — 

— 

— 

C

Sensor GND

• Ambient 

temperature 
sensor

• Passenger 

compartment 
temperature 
sensor

• Evaporator 

temperature 
sensor

• Air mix actuator

• Airflow mode 

actuator

Under any condition

1.0 or less

• Climate control unit: terminal voltage 

(D)

D

GND

Body ground

Under any condition

1.0 or less

• Wiring harness: continuity (Climate 

control unit— GND: D— GND)

E

Solar 
radiation 
sensor input

Solar radiation 
sensor

fluorescent light shined 
directly on the solar 
radiation sensor

0.1—0.45

• Wiring harness: continuity (Climate 

control unit—solar radiation sensor: E—
B, J—A)

• Climate control unit: terminal voltage (J)

• Solar radiation sensor

Blocking light to solar 
radiation sensor

0.1 or less

F

Evaporator 
temperature 
sensor input

Evaporator 
temperature sensor

Compared with 
temperature detected 
by evaporator 
temperature sensor

Refer to 

graph 3

• Wiring harness: continuity (Climate 

control unit—evaporator temperature 
sensor: F—B, C—A)

• Wiring harness: short circuit (Climate 

control unit—evaporator temperature 
sensor: F—B)

• Evaporator temperature sensor

• Climate control unit: terminal voltage (D, 

M)

D

F

J

L

M

N

O

P

Q

R

S

T

U

V

A

B

W

X

C

E

G

H

I

K

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CONTROL SYSTEM 

07-40–14

G

Rear 
window 
defroster 
switch

Rear window 
defroster relay

Rear window defroster 
switch OFF

B+

• Wiring harness: continuity, short circuit 

(Climate control unit— rear window 
defroster relay: G— E)

• Rear window defroster relay

Rear window defroster 
switch ON

0.06

• Climate control unit: terminal voltage (D, 

M)

• Climate control unit

H

Passenger 
compartmen
t 
temperature 
sensor input

Passenger 
compartment 
temperature sensor

Compared with 
temperature detected 
by passenger 
compartment 
temperature sensor

Refer to 

graph 2

• Wiring harness: continuity (Climate 

control unit—passenger compartment 
temperature sensor: H—B, C—A)

• Wiring harness: short circuit (Climate 

control unit—passenger compartment 
temperature sensor: H—B)

• Passenger compartment temperature 

sensor

• Climate control unit: terminal voltage (D, 

M)

I

Motor 
operation

Air intake actuator

Moving towards 
RECIRCULATE

10.75

• Wiring harness: continuity, short circuit 

(Climate control unit— air intake 
actuator: I— F, K— D)

• Air intake actuator

Moving towards 
FRESH

0.72

J

+5V

• Air mix actuator

• Airflow mode 

actuator

• Solar radiation 

sensor

IG SW ON

5.11

• Wiring harness: short circuit (Climate 

control unit—air mix actuator, airflow 
mode actuator, Solar radiation sensor: 
J—A, B, A)

• Air mix actuator

• Airflow mode actuator

• Solar radiation sensor

• Climate control unit: terminal voltage (D, 

M)

IG SW OFF

0.01

• Climate control unit replacement

K

Motor 
operation

Air intake actuator

Moving towards 
FRESH

10.89

• Wiring harness: continuity, short circuit 

(Climate control unit— air intake 
actuator: K— D, I— F)

• Air intake actuator

Moving towards 
RECIRCULATE

0.72

L

Ambient 
temperature 
sensor input

Ambient 
temperature sensor

Compared with 
temperature detected 
by ambient 
temperature sensor

Refer to 

graph 1

• Wiring harness: continuity (Climate 

control unit—ambient temperature 
sensor: C—A, L—B)

• Wiring harness: short circuit (Climate 

control unit—ambient temperature 
sensor: L—B)

• Ambient temperature sensor

• Climate control unit: terminal voltage (D, 

M)

M

IG2

A/C 10 A fuse

IG SW ON

B+

• Wiring harness: continuity, short circuit 

(Climate control unit—  fuse: M— A/C 
10 A)

• A/C 10 A fuse

IG SW OFF

1.0 or less

• Wiring harness: continuity, short circuit 

(Climate control unit—  fuse: M— A/C 
10 A)

N

Potentiomet
er input

Air mix actuator

Set temperature at 
MAX COLD

0.72

• Wiring harness: continuity, short circuit 

(Climate control unit—  air mix actuator: 
N— C)

• Air mix actuator

• Climate control unit: terminal voltage (J)

Set temperature at 
MAX HOT

4.42

O

Motor 
operation

Airflow mode 
actuator

Moving towards VENT

10.39

• Wiring harness: continuity, short circuit 

(Climate control unit— airflow mode 
actuator: O— D, Q— F)

• Airflow mode actuator

Moving towards 
DEFROSTER

0.74

Term

inal

Signal 

name

Connected to

Measurement 

condition

Voltage (V)

Inspection item (s)

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CONTROL SYSTEM 

07-40–15

07-40

P

Potentiomet
er input

Airflow mode 
actuator

VENT

4.41

• Wiring harness: continuity, short circuit 

(Climate control unit—  airflow mode 
actuator: P— C)

• Airflow mode actuator

• Climate control unit: terminal voltage (J)

BILEVEL

3.54

HEAT

2.60

HEAT/DEF

1.69

DEFROSTER

0.74

Q

Motor 
operation

Airflow mode 
actuator

Moving towards 
DEFROSTER

9.98

• Wiring harness: continuity, short circuit 

(Climate control unit— airflow mode 
actuator: Q— F, O— D)

• Airflow mode actuator

Moving towards VENT

0.70

R

B+

ROOM 15 A fuse

Under any condition

B+

• Wiring harness: continuity, short circuit 

(Climate control unit—  fuse: R— 
ROOM 15 A)

• ROOM 15 A fuse

S

Motor 
operation

Air mix actuator

Moving towards HOT

10.91

• Wiring harness: continuity, short circuit 

(Climate control unit— air mix actuator: 
S— F, U— D)

• Air mix actuator

Moving towards COLD

0.70

T

Blower 
motor feed 
back

• Blower motor

• Power MOS 

FET

Fan stopped

11.84

1. Wiring harness: continuity, short circuit 

(Climate control unit— blower motor: 
T— A) (Climate control unit— power 
MOS FET: T— B, V— E) (Blower 
motor— blower relay: B— A) (Blower 
relay— fuse: D— BLOWER 40 A)

2. Wiring harness: continuity (Power MOS 

FET— body ground: A— GND) (Blower 
relay— ground: A— GND)

3. Power MOS FET
4. Blower motor
5. Blower relay
6. BLOWER 40 A fuse
7. A/C 10 A fuse
8. Power MOS FET replacement

Fan: manual LO

7.29

Fan: manual HI

0.20

U

Motor 
operation

Air mix actuator

Moving towards COLD

10.96

• Wiring harness: continuity, short circuit 

(Climate control unit— air mix actuator: 
U— D, S— F)

• Air mix actuator

Moving towards HOT

0.70

V

Blower fan 
speed 
control

Power MOS FET

Fan stopped

0.07

1. Climate control unit: terminal voltage (T)

Fan: manual LO

3.10

Fan: manual HI

7.23

W

TNS signal

TNS relay

Headlight switch OFF

1.0 or less

• Wiring harness: short circuit (Climate 

control unit— TNS relay: W— C)

• TNS relay

• Headlight switch

Headlight switch ON

B+

• Wiring harness: continuity, short circuit 

(Climate control unit— TNS relay: W— 
C)

• TNS relay

• Headlight switch

X

Illumination 
control

Instrument cluster

Headlight switch ON 
and panel light control 
switch at max

0.31

• Wiring harness: continuity (Climate 

control unit— instrument cluster: X— 
2H) (Instrument cluster— body ground: 
2A— GND)

• Instrument cluster

Headlight switch ON 
and panel light control 
switch at min

9.56

• Wiring harness: short circuit (Climate 

control unit— instrument cluster: X— 
2H)

Term

inal

Signal 

name

Connected to

Measurement 

condition

Voltage (V)

Inspection item (s)

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CONTROL SYSTEM 

07-40–16

End Of Sie

CLIMATE CONTROL UNIT INSPECTION [MANUAL AIR CONDITIONER]

id074000803500

1. Remove the climate control unit. (See 07-40-25 CLIMATE CONTROL UNIT REMOVAL [MANUAL AIR 

CONDITIONER].)

2. Disconnect the air mix wire from the climate control unit
3. Install the audio unit. (See 09-20-4 AUDIO UNIT REMOVAL/INSTALLATION.)
4. Connect the climate control unit connector.
5. Connect the negative (-) lead of the tester to body ground.
6. Turn the ignition switch to the ON position.
7. By inserting the positive (+) lead of the tester into each 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 climate control unit.

Terminal Voltage Table (Reference)

-20

0

1

2

3

4

5

{-4}

{14}

{32}

{50}

{68}

{86} {104} {122}

-10

TEMPERATURE

V

O

LT

A

GE(V)

0

20

10

30

40

50

{  F}

C

Graph 1 (Ambient temperature sensor)

-20

0

1

2

3

4

5

{-4}

{14}

{32}

{50}

{68}

{86} {104} {122}

-10

TEMPERATURE

V

O

LT

A

GE(V)

0

20

10

30

40

50

{  F}

C

Graph 2 (Passenger compartment temperature sensor)

-20

0

1

2

3

4

5

{-4}

{14}

{32}

{50}

{68}

{86} {104} {122}

-10

TEMPERATURE

V

O

LT

A

GE(V)

0

20

10

30

40

50

{  F}

C

Graph 3 (Evaporetor temperature sensor)

D

F

J

L

M

N

O

P

Q

R

S

T

U

V

A

B

W

X

C

E

G

H

I

K

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