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Mazda CX-9 Grand Touring. Manual - part 441

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (OPEN CIRCIT
BETWEEN REAR BLOWER RELAY AND
GROUND) OR ELSEWHERE



Measure the voltage at the following rear blower
relay terminal.



Terminal E (GND signal)



Is the voltage approx. 0 V?

Yes Go to the next step.

Repair or replace for open circuit

between rear blower relay and GND,

then go to Step 13.

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (OPEN OR SHORT
CIRCUIT BETWEEN REAR BLOWER RELAY
AND REAR BLOWER MOTOR) OR
ELSEWHERE



Measure the voltage at the following rear blower
relay terminal.



Terminal B (blower motor operation signal)



Is the voltage approx. 12 V?

Yes

Repair or replace for open or short
circuit between rear blower relay and
rear blower motor, then go to Step
13.

Replace the rear blower relay, then

go to Step 13.

INSPECT TO SEE WHETHER MALFUNCTION
IS IN REAR BLOWER MOTOR OR ELSEWHERE



Measure the voltage at the following rear blower
motor terminal.



Terminal A (blower motor operation signal)



Is the voltage approx. 12 V?

Yes Go to the next step.

Replace the rear blower motor, then

go to Step 13.

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (OPEN OR SHORT
CIRCUIT BETWEEN REAR BLOWER MOTOR
AND REAR POWER MOS FET) OR ELSEWHERE



Measure the voltage at the following rear power
MOS FET terminal.



Terminal B (blower motor operation signal)



Is the voltage approx. 12 V?

Yes Go to the next step.

Repair or replace for open or short

circuit between rear blower motor

and rear power MOS FET, then go to

Step 13.

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (OPEN CIRCUIT
BETWEEN REAR POWER MOS FET AND
GROUND) OR ELSEWHERE



Is there continuity at the following terminals?



Terminal (wiring harness-side connector)
A-GND

Yes Go to the next step.

Repair or replace for open circuit

between rear power MOS FET and

GND, then go to Step 13.

INSPECT REAR A/C UNIT

2008 Mazda CX-9 Grand Touring

2008 HVAC Symptom Troubleshooting (HVAC) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:14:51 AM

Page 20

NO.8 AIR FROM FRONT/REAR VENTS NOT COLD ENOUGH

NO.8 AIR FROM FRONT/REAR VENTS NOT COLD ENOUGH DESCRIPTION AND POSSIBLE
CAUSE



Inspect the fan in rear A/C unit.



Is the fan free of interference with the rear
A/C unit case?



Is the fan free of foreign material and
obstructions?



Is the fan normal?

Yes Go to the next step.

Remove obstruction, repair or

replace the fan blower unit case, then

go to Step 13.

11*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (OPEN CIRCUIT
BETWEEN REAR POWER MOS FET AND
CLIMATE CONTROL UNIT) OR ELSEWHERE



Turn the ignition switch to LOCK position.



Disconnect the front climate control unit
connector (24-pin).



Is there continuity following terminals at harness-
side connector.



Terminal D (rear power MOS FET) and
terminal 1T (front climate control unit)



Terminal C (rear power MOS FET) and
terminal 1V (front climate control unit)

Yes

Replace the rear power MOS FET,
then go to the next step.

Repair or replace for open circuit

between the rear power MOS FET

and the front climate control unit,

then go to Step 13.

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



Is the air discharged from rear vent after replace
the rear power MOS FET?

Yes

Troubleshooting completed. Explain
repairs to customer.

Replace the front climate control

unit, then go to the next step.

VERIFY REPAIR



Is the air discharged from rear vent?

Yes

Troubleshooting completed. Explain
repairs to customer.

Recheck malfunction symptoms,

then repeat from Step 1 if the

malfunction recurs.

Air from front/rear vents not cold enough.

DESCRIPTION



Malfunction in A/C basic system



Magnetic clutch operates but A/C system malfunctions.

POSSIBLE



Drive belt malfunction



A/C unit or condenser malfunction



Receiver/drier or expansion valve malfunction (valve closes too much)

2008 Mazda CX-9 Grand Touring

2008 HVAC Symptom Troubleshooting (HVAC) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:14:51 AM

Page 21

DIAGNOSTIC PROCEDURE

NO.8 AIR FROM FRONT/REAR VENTS NOT COLD ENOUGH DIAGNOSTIC PROCEDURE

CAUSE



Malfunction in refrigerant lines



A/C compressor system malfunction, insufficient compressor oil



Over filling of compressor oil, malfunction in expansion valve or A/C unit air
mix link system

STEP

INSPECTION

ACTION

INSPECT DRIVE BELT



Inspect the drive belt.

(See DRIVE BELT
INSPECTION [MZI-3.7] .)



Is it normal?

Yes Go to the next step.

Adjust or replace the drive belt, then go to Step 20.

(See DRIVE BELT

REMOVAL/INSTALLATION [MZI-3.7] .)

INSPECT REFRIGERANT SYSTEM
PERFORMANCE



Perform refrigerant system
performance test. (See
REFRIGERANT SYSTEM
PERFORMANCE TEST .)



Is the operation normal?

Yes

Operation is normal. (Recheck malfunction
symptoms.)

Go to the next step.

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



Are the refrigerant high-pressure
and low-pressure values both high?

Yes Go to the next step.

Go to Step 6.

INSPECT A/C UNIT INTAKE



Is the A/C unit intake clogged?

Yes

Remove obstruction, then go to Step 20. (If air does
not reach the evaporator in the A/C unit, heat
exchange does not occur and refrigerant pressure
becomes high. Therefore, removal of obstruction is
necessary.)

Go to the next step.

INSPECT CONDENSER



Inspect the condenser.

(See CONDENSER
INSPECTION .)

Yes

Adjust refrigerant to the specified amount, then go
to Step 20. (Excessive amount of refrigerant.)

Replace the condenser, or repair and clean the

2008 Mazda CX-9 Grand Touring

2008 HVAC Symptom Troubleshooting (HVAC) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:14:51 AM

Page 22



Is it normal?

condenser fins, then go to Step 20.

INSPECT TO SEE WHETHER
MALFUNCTION IS IN EXPANSION
VALVE, RECEIVER/DRIER AND
REFRIGERANT LINES OR
ELSEWHERE



Are the refrigerant high-pressure
and low-pressure values low?

Yes Go to the next step.

Go to Step 14.

INSPECT TO SEE WHETHER
MALFUNCTION IS IN EXPANSION
VALVE AND RECEIVER/DRIER OR
ELSEWHERE



Immediately after the A/C
compressor operates, does the
refrigerant high-pressure value
momentarily rise to correct value,
then fall and stay below it? (Is there
negative pressure on low-pressure
side?)

Yes Go to the next step.

Go to Step 10.

INSPECT TO SEE WHETHER
MALFUNCTION IS IN EXPANSION
VALVE OR RECEIVER/DRIER



Turn the A/C switch off and let the
air conditioner stop for 10 min.



Start the engine.



Turn the both A/C switch and fan
switch on.



Does the malfunction occur after
the A/C compressor turns on?

Yes Go to the next step.

Replace the condenser and vacuum the refrigerant

line more than 30 min by the vacuum pump, add

refrigerant to the specified level, then go to Step 20.

(Since water has intermixed in the receiver/drier

and it is saturated, replacement is necessary.)

VERIFY THAT EXPANSION VALVE
HEAT-SENSING TUBE WITHIN A/C
UNIT IS POSITIONED SECURELY
AND CORRECTLY



Is the expansion valve heat-sensing
tube in the A/C unit securely
installed in the proper position?

Yes

Replace the expansion valve, then go to Step 20.
(Since the valve closes too much, replacement is
necessary.)

Install the heat-sensing tube securely in the proper

position, then go to Step 20.

INSPECT REFRIGERANT LINE



Inspect the refrigerant lines.



Is the piping free of damage
and cracks?

Yes Go to the next step.

2008 Mazda CX-9 Grand Touring

2008 HVAC Symptom Troubleshooting (HVAC) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:14:51 AM

Page 23

Content .. 439 440 441 442 ..