Mazda CX 7. Manual — part 283

SYMPTOM TROUBLESHOOTING

07-03–5

07-03

End Of Sie

NO.2 AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE

id070300800500

Full-auto Air Conditioner

• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while

performing the inspection to discover whether poor contact points are the cause of any intermittent
malfunctions. If there is a problem, inspect make sure connectors, terminals and wiring harnesses are
connected correctly and undamaged.

Diagnostic procedure

2

Amount of air blown from vents does not change.

DESCRIPTION

• Malfunction in blower system

POSSIBLE

CAUSE

• A/C unit malfunction

• Blower motor malfunction

• Malfunction in power MOS FET system

• Climate control unit malfunction

STEP

INSPECTION

ACTION

1

INSPECT HEATER BLOWER 40 A FUSE

• Inspect the HEATER BLOWER 40 A fuse.

• Is it normal?

Yes

Go to the next step.

No

Replace the fuse, then go to Step 15. If the fuse burns out
immediately, go to the next step.

2

INSPECT TO SEE WHETHER MALFUNCTION
IS IN A/C UNIT OR ELSEWHERE

• Turn the ignition switch to the ON position.

• Turn the airflow volume control dial to ON

position.

• Recirculate air inside the vehicle.

• Does the blower motor rotate smoothly?

Yes

Go to Step 4.

No

Go to the next step.

3

INSPECT A/C UNIT INTAKE VENT

• Is A/C unit intake vent clogged?

Yes

Remove obstruction, then go to Step 15.

No

Inspect if there are any obstruction in the A/C unit passage,
then go to Step 15.

4*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN BLOWER RELAY SYSTEM OR POWER
MOS FET SYSTEM

• Turn the ignition switch to ON position.

• Turn the airflow volume control dial to OFF

position.

• Measure the voltage at the following blower

motor terminal.
— Terminal A (blower motor operation

signal)

• Is voltage approx. 12 V?

Yes

Go to Step 8.

No

Go to the next step.

5*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN FUSE BLOCK AND
BLOWER RELAY) OR ELSEWHERE

• Measure the voltage at the following blower

relay terminals.
— Terminal B (IG2 signal)

— Terminal A (B+ signal)

• Is the voltage approx. 12 V?

Yes

Go to the next step.

No

Repair the wiring harness between the blower relay and
HEATER BLOWER 40 A fuse, then go to Step 15.

6*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN BLOWER RELAY
AND GROUND) OR ELSEWHERE

• Measure the voltage at the following blower

relay terminal.

— Terminal D (GND signal)

• Is the voltage approx. 0 V?

Yes

Go to the next step.

No

Repair the wiring harness between the blower relay and
ground, then go to Step 15.

7*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN BLOWER RELAY
AND BLOWER MOTOR) OR BLOWER RELAY

• Measure the voltage at the following blower

relay terminal.
— Terminal C (blower motor operation

signal)

• Is the voltage approx. 12 V?

Yes

Repair the wiring harness between the blower relay and
blower motor, then go to Step 15.

No

Replace the blower relay, then go to Step 15.

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SYMPTOM TROUBLESHOOTING

07-03–6

End Of Sie

8*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN BLOWER MOTOR OR ELSEWHERE

• Measure the voltage at the following blower

motor terminal.

— Terminal A (blower motor operation

signal)

• Is the voltage approx. 12 V?

Yes

Go to the next step.

No

Inspect the blower motor, then go to Step 15.

9*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN BLOWER MOTOR
AND POWER MOS FET) OR ELSEWHERE

• Measure the voltage at the following terminal

of power MOS FET.

— Terminal E (blower motor operation

signal)

• Is voltage approx. 12 V?

Yes

Go to the next step.

No

Repair the wiring harness between the blower motor and
power MOS FET, then go to Step 15.

10*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN POWER MOS FET
AND GROUND) OR ELSEWHERE

• Measure the voltage at the following power

MOS FET terminal.

— Terminal A (blower motor operation

signal)

• Is the voltage approx. 0 V?

Yes

Go to the next step.

No

Repair the wiring harness between the power MOS FET
and ground, then go to Step 15.

11

INSPECT A/C UNIT

• Inspect the fan in A/C unit.

— Is the fan free of interference with the A/C

unit case?

— Is the fan free of foreign material and

obstruction?

• Is the fan normal?

Yes

Go to the next step.

No

Remove obstruction, repair or replace the fan and A/C unit
case, then go to Step 15.

12*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN POWER MOS FET OR ELSEWHERE

• Disconnect power MOS FET connector.

• Turn the airflow volume control dial to 1st

position from OFF.

• Measure the voltage at the following power

MOS FET terminal.

— Terminal B (blower motor control signal)

• Is voltage approx. 10 V?

Yes

Replace the power MOS FET, then go to Step 15.

No

Go to the next step.

13*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (LACK OF
CONTINUITY BETWEEN POWER MOS FET
AND CLIMATE CONTROL UNIT) OR
ELSEWHERE

• Turn the ignition switch to the LOCK position.

• Disconnect climate control unit connector.

• Inspect for continuity at the following

terminals between the power MOS FET and
climate control unit.

— Terminal B— T (blower motor control

signal)

— Terminal E— V (blower motor feedback

signal)

• Is there continuity?

Yes

Go to the next step.

No

Repair the wiring harness between the power MOS FET
and climate control unit, then go to Step 15.

14*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN CLIMATE CONTROL UNIT OR WIRING
HARNESS (SHORT TO GROUND IN WIRING
HARNESS BETWEEN POWER MOS FET AND
CLIMATE CONTROL UNIT)

• Inspect for continuity at the following terminal

between the power MOS FET and ground.

— Terminal A (blower motor control signal)—

ground

• Is there continuity?

Yes

Repair the wiring harness between the power MOS FET
and ground, then go to the next step.

No

Replace the climate control unit, then go to the next step.

15

CONFIRM THAT MALFUNCTION SYMPTOM
DOES NOT RECUR AFTER REPAIR

• Is air discharged from vent?

Yes

Troubleshooting completed.
Explain repairs to customer.

No

Recheck malfunction symptoms, then repeat from Step 1 if
the malfunction recurs.

STEP

INSPECTION

ACTION

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SYMPTOM TROUBLESHOOTING

07-03–7

07-03

NO.3 AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE

id070300800600

Manual Air Conditioner

Diagnostic procedure

End Of Sie

NO.4 AIR INTAKE MODE DOES NOT CHANGE

id070300800700

• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while

performing the inspection to discover whether poor contact points are the cause of any intermittent
malfunctions. If there is a problem, inspect to make sure connectors, terminals and wiring harnesses are
connected correctly and undamaged.

Diagnostic procedure

3

Amount of air blown from vents does not change.

DESCRIPTION

• Malfunction in blower system

POSSIBLE

CAUSE

• Blower relay, blower motor, resistor, airflow volume control dial malfunction

• A/C unit malfunction

STEP

INSPECTION

ACTION

1

INSPECT BLOWER SYSTEM

• Inspect the following systems and electrical

parts.
— Blower relay

— Blower motor

— Resistor

— Airflow volume control dial

— Related wiring harnesses

• Are they normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part, then go to Step 5.

2

INSPECT TO SEE WHETHER MALFUNCTION
IS IN A/C UNIT OR ELSEWHERE

• Turn the ignition switch to the ON position.

• Turn the airflow volume control dial on.

• Recirculate air inside the vehicle.

• Does the blower motor rotate smoothly?

Yes

Go to Step 4.

No

Go to the next step.

3

INSPECT A/C UNIT

• Inspect blower motor.

— Is the fan free of interference from the A/C

unit case?

— Is the fan free of foreign material and

obstructions?

• Is the fan normal?

Yes

Go to the next step.

No

Remove obstruction, repair or replace the fan and A/C unit
case, then go to Step 5.

4

INSPECT A/C UNIT INTAKE VENT

• Is the A/C unit intake vent clogged?

Yes

Remove obstruction, then go to the next step.

No

Inspect if there are any obstructions in the A/C unit passage,
then go to the next step.

5

VERIFY THAT MALFUNCTION SYMPTOM
OCCURS AFTER REPAIR

• Does air blow out?

Yes

Troubleshooting completed.
Explain repairs to customer.

No

Recheck malfunction symptoms, then repeat from Step 1 if
the malfunction recurs.

4

Air intake mode does not change.

DESCRIPTION

• Air intake mode does not change when switching REC/FRESH mode.

POSSIBLE

CAUSE

• Air intake actuator malfunction

• Air intake door malfunction

STEP

INSPECTION

ACTION

1*

INSPECT AIR INTAKE ACTUATOR
(Auto A/C)

• Inspect the following items using M-MDS

simulation function.

— MIX_ACT (Air intake actuator)

• Is it okay?

(Manual A/C)

• Inspect air intake actuator.

• Is it okay?

Yes

Go to the next step.

No

Replace the air intake actuator, then go to Step 9.

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SYMPTOM TROUBLESHOOTING

07-03–8

2*

INSPECT TO SEE WHETHER MALFUNCTION
(LACK OF CONTINUITY) IS IN AIR INTAKE
ACTUATOR, WIRING HARNESS (BETWEEN
CLIMATE CONTROL UNIT AND AIR INTAKE
ACTUATOR) OR ELSEWHERE

• Turn the ignition switch to the ON position.

• Measure the voltages at the following climate

control unit terminals.

(Auto A/C)

— Terminal K (24-pin, FRESH motor drive

signal)

— Terminal I (24-pin, RECIRCULATE motor

drive signal)
(See 07-40-13 CLIMATE CONTROL UNIT
INSPECTION [FULL-AUTO AIR
CONDITIONER].)

(Manual A/C)

— Terminal X (24-pin, FRESH motor drive

signal)

— Terminal V (24-pin, RECIRCULATE motor

drive signal)

• Are voltages normal?

Yes

Go to the next step.

No

Go to Step 4.

3*

INSPECT TO SEE WHETHER MALFUNCTION
(LACK OF CONTINUITY) IS IN AIR INTAKE
ACTUATOR OR WIRING HARNESS
(BETWEEN CLIMATE CONTROL UNIT AND
AIR INTAKE ACTUATOR)

• Measure the voltages at the following air

intake actuator terminals.
(Auto A/C / Manual A/C)
— Terminal D (FRESH motor drive signal)

— Terminal F (RECIRCULATE motor drive

signal)

• Are voltages as shown below?

(Auto A/C / Manual A/C)

— Terminal D: approx. 0.5 V during

RECIRCULATE and approx. 10 V during
FRESH

— Terminal F: approx. 10 V during

RECIRCULATE and approx. 0.5 V during
FRESH

Yes

Go to Step 7.

No

Repair the wiring harness between the climate control unit
and air intake actuator, then go to Step 9.

4

INSPECT TO SEE WHETHER MALFUNCTION
IS IN AIR INTAKE ACTUATOR OR
ELSEWHERE

• Disconnect the air intake actuator connector.

• Measure the voltages at the following climate

control unit terminals.

(Auto A/C)

— Terminal K (FRESH motor drive signal)

— Terminal I (RECIRCULATE motor drive

signal)
(See 07-40-13 CLIMATE CONTROL UNIT
INSPECTION [FULL-AUTO AIR
CONDITIONER].)

(Manual A/C)

— Terminal X (FRESH motor drive signal)

— Terminal V (RECIRCULATE motor drive

signal)

• Are voltages normal?

Yes

Inspect the air intake actuator, then go to Step 9.

No

Go to the next step.

STEP

INSPECTION

ACTION

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