Mazda 6. Manual - part 391

U–68

TROUBLESHOOTING 

End Of Sie

NO.4 AIR INTAKE MODE DOES NOT CHANGE

A6E858001038W06

• 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, check to make sure connectors, terminals and wiring harnesses are 
connected correctly and undamaged.

Diagnostic procedure

3

INSPECT BLOWER UNIT

• Inspect fan in blower unit.

— Is fan free of interference from blower unit 

case?

— Is fan free of foreign material and 

obstructions?

• Is fan okay?

Yes

Go to next step.

No

Remove obstruction, repair or replace fan and blower unit 
case, then go to Step 5.

4

INSPECT BLOWER UNIT INTAKE VENT

• Is blower unit intake vent clogged?

Yes

Remove obstruction, then go to next step.

No

Inspect if there are any obstructions in passage between 
blower unit and A/C unit, then go to 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 
malfunction recurs.

STEP

INSPECTION

ACTION

4

Air intake mode does not change.

DESCRIPTION

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

POSSIBLE 

CAUSE

• Malfunction in air intake actuator (Steps 1—6)

• Malfunction in air intake door (Step 7)

STEP

INSPECTION

ACTION

1*

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 ignition switch to ON position.

• Test voltages at the following terminals of 

climate control unit.
— Terminal 2K (12-pin, FRESH motor drive 

signal)

— Terminal 2I (12-pin, RECIRCULATE 

motor drive signal)

(See 

U–47 Full-auto Air Conditioner

)

• Are voltages okay?

Yes

Go to next step.

No

Go to Step 3.

2*

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

• Test voltages at the following terminals of air 

intake actuator.
— Terminal D (FRESH motor drive signal)
— Terminal F (RECIRCULATE motor drive 

signal)

• Are voltages as shown below?

— Terminal D: approximately 0.5 V during 

RECIRCULATE and approximately 10 V 
during FRESH

— Terminal F: approximately 10 V during 

RECIRCULATE and approximately 0.5 V 
during FRESH

Yes

Replace air intake actuator, then go to Step 8.

No

Repair wiring harness between climate control unit and air 
intake actuator, then go to Step 8.

TROUBLESHOOTING 

U–69

U

End Of Sie

3

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

• Disconnect air intake actuator connector.

• Test voltages at the following terminals of 

climate control unit.
— Terminal 2K (12-pin, FRESH motor drive 

signal)

— Terminal 2I (12-pin, RECIRCULATE 

motor drive signal)

(See 

U–47 Full-auto Air Conditioner

)

• Are voltages okay?

Yes

Inspect air intake actuator, then go to Step 8.

No

Go to next step.

4

INSPECT TO SEE WHETHER MALFUNCTION 
IS IN WIRING HARNESS (SHORT TO B+ 
BETWEEN CLIMATE CONTROL UNIT AND 
AIR INTAKE ACTUATOR) OR ELSEWHERE

• Disconnect climate control unit connector.

• Test voltages at the following terminals of 

climate control unit.
— Terminal 2K (12-pin, FRESH motor drive 

signal)

— Terminal 2I (12-pin, RECIRCULATE 

motor drive signal)

• Are voltages approximately 0 V?

Yes

Go to next step.

No

Repair wiring harness between climate control unit and air 
intake actuator, then go to Step 8.

5

INSPECT TO SEE WHETHER MALFUNCTION 
IS IN WIRING HARNESS (SHORT TO 
GROUND BETWEEN CLIMATE CONTROL 
UNIT AND AIR INTAKE ACTUATOR) OR 
ELSEWHERE

• Turn ignition switch to LOCK position.

• Inspect for continuity at the following 

terminals between climate control unit and 
ground.
— Terminal 2K (12-pin, FRESH motor drive 

signal)

— Terminal 2I (12-pin, RECIRCULATE 

motor drive signal)

• Is there continuity?

Yes

Repair wiring harness between climate control unit and air 
intake actuator, then go to Step 8.

No

Go to next step.

6

INSPECT AIR INTAKE LINK

• Inspect air intake links.

— Is there grease on link?
— Are links securely and properly installed?
— Are links free of obstructions and 

hindrances?

• Are above items okay?

Yes

Go to next step.

No

Apply grease to links. If any links are damaged, replace air 
intake actuator, then go to Step 8.

7

INSPECT TO SEE WHETHER MALFUNCTION 
IS IN CLIMATE CONTROL UNIT OR AIR 
INTAKE DOOR

• Inspect blower unit air intake door.

— Is door free of obstructions, cracks, and 

damage?

— Are doors securely and properly installed?

• Are above items okay?

Yes

Replace climate control unit, then go to next step.

No

Remove obstruction, or install doors in proper position. If 
any doors are cracked or damaged, replace them, then go 
to next step.

8

CONFIRM THAT MALFUNCTION SYMPTOMS 
DO NOT RECUR AFTER REPAIR

• Does air intake mode change smoothly?

Yes

Troubleshooting completed. Explain repairs to customer.

No

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

STEP

INSPECTION

ACTION

U–70

TROUBLESHOOTING 

NO.5 NO TEMPERATURE CONTROL WITH CLIMATE CONTROL UNIT

A6E858001038W07

Diagnostic procedure

End Of Sie

NO.6 WINDSHIELD FOGGED

A6E858001038W08

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

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

5

No temperature control with climate control unit.

DESCRIPTION

• Malfunction in A/C unit and/or climate control unit air mix system.

POSSIBLE 

CAUSE

• A/C unit air mix link, air mix crank, air mix rod, air mix wire, wire clamp malfunction (Steps 2, 3)

• Climate control unit rack-and-pinion, air mix wire malfunction (Step 4)

• A/C unit air mix door malfunction (Steps 5, 6)

• Heater piping malfunction (Step 7)

STEP

INSPECTION

ACTION

1

INSPECT COOLANT TEMPERATURE

• Is coolant sufficiently warmed up?

Yes

Go to next step.

No

Warm engine up, then go to Step 8.

2

INSPECT A/C UNIT AIR MIX SYSTEM

• Inspect A/C unit air mix links, air mix cranks, 

air mix rods, air mix actuator or wire clamp.
— Is there grease on links and cranks?
— Are links, cranks, and rods securely 

installed in their proper positions?

— Is wire clamp free of deformation?

• Are above items okay?

Yes

Go to next step.

No

Apply grease or install links, cranks, and rods securely in 
their proper positions, repair or replace air mix actuator or 
wire clamp, then go to Step 8.

3

VERIFY THAT AIR MIX WIRE FROM A/C UNIT 
IS POSITIONED SECURELY AND 
CORRECTLY (IF AVAILABLE)

• Is air mix wire securely installed in the 

correct position in relation to A/C unit air mix 
links?

Yes

Go to next step.

No

Adjust air mix wire or install securely in correct position, then 
go to Step 8.

4

INSPECT CLIMATE CONTROL UNIT

• Inspect climate control unit. (See 

U–47 

CLIMATE CONTROL UNIT INSPECTION

)

• Is climate control unit okay?

Yes

Go to next step.

No

Repair or replace climate control unit, then go to Step 8.

5

INSPECT A/C UNIT

• Is there any foreign material or obstruction in 

A/C unit air mix doors?

Yes

Remove obstruction, then go to Step 8.

No

Go to next step.

6

INSPECT A/C UNIT AIR MIX DOORS

• Is A/C unit air mix door securely and properly 

installed?

Yes

Inspect air mix door for cracks or damage, then go to next 
step.

No

Install air mix door securely in proper position, then go to 
next step.

7

INSPECT HEATER LINES

• Inspect heater lines.

— Is heater piping free of damage and 

cracks?

— Are heater piping connections free of 

engine coolant leakage?

— Are heater piping connections securely 

tightened?

— Are heater piping installation points on A/

C unit free of engine coolant leakage?

• Are above items okay?

Yes

Operation is okay. Recheck malfunction symptoms.

No

If heater piping connections is loosed, tighten connections 
with specified torque.
Repair or replace heater piping, then go to next step.

8

VERIFY THAT MALFUNCTION SYMPTOM 
OCCURS AFTER REPAIR

• Does unit operate in every temperature 

setting?

Yes

Troubleshooting completed.
Explain repairs to customer.

No

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

6

Windshield fogged.

DESCRIPTION

• A/C compressor does not operate while airflow mode is in DEFROSTER or HEAT/DEF modes.

• Air intake mode does not change to FRESH while airflow mode is in DEFROSTER or HEAT/DEF 

modes.

TROUBLESHOOTING 

U–71

U

Diagnostic procedure

POSSIBLE 

CAUSE

• Climate control unit (B+ signal) system malfunction (Steps 2, 4, 5)

• Air intake actuator malfunction (Steps 3, 7)

• Climate control unit (RECIRCULATE, FRESH signal) system malfunction (Steps 9—11)

• Malfunction in blower unit air intake doors (Steps 12, 13)

STEP

INSPECTION

ACTION

1

COOL AIR BLOW OUT INSPECTION

• When both A/C and fan switch in climate 

control unit are on, does cool air blow out 
from front vent?

Yes

Go to next step.

No

Go to Step 1 of troubleshooting index No.8.

2

INSPECT CLIMATE CONTROL UNIT POWER 
SUPPLY FUSE FOR B+ SIGNAL

• Is climate control unit power supply fuse for 

B+ signal okay?

Yes

Go to next step.

No

Inspect for a short to ground on blown fuse circuit.

• Repair or replace as necessary. Install appropriate 

amperage fuse.

3

INSPECT AIR INTAKE ACTUATOR

• Inspect air intake actuator.

— Is there grease on link?
— Is link securely and properly positioned?
— Is link free of obstructions?

• Are above items okay?

Yes

Go to next step.

No

Apply grease or install link properly and securely, remove 
obstruction, then go to Step 14.

*4

INSPECT WIRING HARNESS BETWEEN 
FUSE BLOCK AND CLIMATE CONTROL UNIT 
FOR CONTINUITY

• Disconnect climate control unit connector 

(12-pin).

• Turn ignition switch to ON position.

• Test voltage at climate control unit connector 

terminal F (B+ signal).

• Is voltage approximately 12 V?

Yes

Go to next step.

No

Repair wiring harness between fuse block and climate 
control unit, then go to Step 14.

*5

INSPECT WIRING HARNESS BETWEEN 
CLIMATE CONTROL UNIT AND GROUND 
FOR VOLTAGE

• Test voltage at climate control unit connector 

terminal 2L (Ground).

• Is voltage approximately 0V?

Yes

Go to next step.

No

Repair wiring harness between climate control unit and 
ground, then go to Step 14.

6

VERIFY WHETHER MALFUNCTION IS IN 
BLOWER UNIT AIR INTAKE DOOR OR 
ELSEWHERE

• Turn ignition switch to LOCK position.

• Connect climate control unit connector (12-

pin).

• Remove air intake actuator.

• Turn ignition switch to ON position.

• Set fan switch to 4th position.

• Does air intake mode (RECIRCULATE, 

FRESH) change smoothly when air intake 
link is operated by hand?

Yes

Go to next step.

No

Go to Step 12.

7

INSPECT AIR INTAKE ACTUATOR

• Inspect air intake actuator.

(See 

U–30 AIR INTAKE ACTUATOR 

INSPECTION

)

• Is it okay?

Yes

Go to next step.

No

Replace air intake actuator, go to Step 14.

8

INSPECT AIR INTAKE SELECTOR SWITCH 
AND DEFROSTER SWITCH IN CLIMATE 
CONTROL UNIT

• Test voltage at climate control unit connector 

(12-pin) terminals 2K and 2I.

• Is it okay?

Yes

Go to next step.

No

Replace climate control unit, then go to Step 14.