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2014 - Mazda6 - HVAC

NO.4 NO TEMPERATURE CONTROL WITH CLIMATE CONTROL UNIT [FULL-AUTO AIR CONDITIONER]



4

No temperature control with climate control unit

DESCRIPTION

  • Temperature does not change when operating temperature dial

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

  • Malfunction in driver and/or passenger side air mix actuator or related wiring harness

POSSIBLE CAUSE

  • A/C unit air mix link, air mix crank, air mix rod, malfunction

  • Climate control unit rack-and-pinion, malfunction

  • A/C unit air mix door malfunction

  • Heater piping malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1

 INSPECT COOLANT TEMPERATURE

  • Is the coolant sufficiently warmed up?

Yes

Go to the next step.

No

Warm up the engine, then go to Step 20.

2*

 INSPECT CLIMATE CONTROL UNIT POWER SUPPLY FUSE FOR B+ SIGNAL

  • Is the climate control unit power supply fuse for B+ signal normal?.

Yes

Go to the next step.

No

Inspect for a short to ground in blown fuse circuit.

Repair or replace if necessary.

Install appropriate amperage fuse, then go to Step 20.

3*

 INSPECT TO SEE WHETHER MALFUNCTION (OPEN CIRCUIT) IS IN B+ SIGNAL WIRING HARNESS (BETWEEN FUSE BLOCK AND CLIMATE CONTROL UNIT) OR ELSEWHERE

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

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

  • Measure voltage at climate control unit harness-side connector (24-pin) terminal 1B (B+ signal).

  • Is the voltage approx. 12 V?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between fuse block terminal and climate control unit terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has an open circuit.

Go to Step 20.

4*

 INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) WIRING HARNESS (BETWEEN CLIMATE CONTROL UNIT AND GROUND) OR ELSEWHERE

  • Climate control unit connector (24-pin) disconnected.

  • Verify that continuity between climate control unit harness-side connector (24-pin) terminal 1A and ground.

  • Is the continuity?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and ground.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 20.

5*

 INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER UNIT OR AIR MIX ACTUATOR

  • Reconnect the disconnected climate control unit connector.

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

  • Measure the voltage at climate control unit terminal 2G (drive-side) and 2E (passenger-side) (24-pin) when temperature control dial at MAX HOT and MAX COLD.

    (See CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER].)

  • Is voltage normal?

Yes

Go to Step 16.

No

Go to the next step.

6*

 INSPECT TO SEE WHETHER MALFUNCTION IS IN POSITION SENSOR OR ELSEWHERE

Yes

Go to Step 9.

No

Go to the next step.

7*

 INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY OR SHORT TO BATTERY POWER OR GROUND) IS IN POSITION SENSOR POWER SUPPLY (CLIMATE CONTROL UNIT TERMINAL 1N) OR ELSEWHERE

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

  • Measure voltage at climate control unit terminal 1N (24-pin).

  • Is voltage approx. 5 V?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and airflow mode actuator / air mix actuator terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 20.

8*

 INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY OR OPEN) IS IN POSITION SENSOR GROUND (CLIMATE CONTROL UNIT TERMINAL 1J) OR ELSEWHERE

  • Measure voltage at climate control unit terminal 1J (24-pin).

  • Is the voltage below. 1.0 V?

Yes

Go to Step 12.

No

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and airflow mode actuator / air mix actuator terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 20.

9

 INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO POWER SUPPLY) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR ELSEWHERE

  • Is climate control unit terminal 2G (driver-side) and 2E (passenger-side) voltage approx. 12V, at Step 5?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and airflow mode actuator / air mix actuator terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 20.

No

Go to the next step.

10*

 INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR ELSEWHERE

  • Switch the ignition off.

  • Disconnect the climate control unit and air mix actuator connectors.

  • Verify continuity between climate control unit terminal 2G (driver-side) and 2E (passenger-side) (24-pin) and each side air mix actuator terminal F at harness-side connector.

  • Is there continuity?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and each side air mix actuator terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 20.

11*

 INSPECT TO SEE WHETHER MALFUNCTION (SHORT TO GROUND) IS IN WIRING HARNESS (AIR MIX POSITION SIGNAL) OR POSITION SENSOR COMMON (POWER SUPPLY OR GROUND) HARNESS

  • Climate control unit and air mix actuator connectors disconnected.

  • Verify continuity between climate control unit harness-side connector terminal 2G (driver-side) and 2E (passenger-side) (24-pin) and ground.

  • Is there continuity?

Yes

Repair wiring harness for short to ground between climate control unit terminal 2G (driver-side) and 2E (passenger-side) and each side air mix actuator terminal F.

Then go to Step 20.

No

Inspect and repair for open circuit following:

  • Between driver side air mix actuator terminal G and junction point to airflow mode actuator (position sensor power supply).

  • Between passenger side air mix actuator terminal E and junction point to airflow mode actuator (position sensor power supply).

  • Between driver side air mix actuator terminal E and junction point to airflow mode actuator (position sensor ground).

  • Between passenger side air mix actuator terminal G and junction point to airflow mode actuator (position sensor ground).

Then go to Step 20.

12*

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

  • Disconnect the air mix actuator connectors.

  • Measure voltage at the following terminals of air mix actuator.

    • Terminal C (driver-side)/B (passenger-side) (COLD motor drive signal)

    • Terminal B (driver-side)/C (passenger-side) (HOT motor drive signal)

  • Are voltage s as shown below?

    • COLD motor drive signal: approx. 10 V during COLD and approx. 0.5 V during HOT

    • HOT motor drive signal: approx. 0.5 V during COLD and approx. 10 V during HOT

Yes

Go to Step 16.

No

Go to the next step.

13*

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

  • Air mix actuator connectors disconnected.

  • Disconnect the climate control unit connector.

  • Measure voltage at the following terminals of the climate control unit harness-side connector.

      • Driver-side:

    • Terminal 2B (12-pin, COLD motor drive signal)

    • Terminal 2D (12-pin, HOT motor drive signal)

      Passenger-side

    • Terminal 2H (12-pin, COLD motor drive signal)

    • Terminal 2F (12-pin, HOT motor drive signal)

  • Are voltages approx. 0 V?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 20.

14*

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

  • Air mix actuator connectors disconnected.

  • Switch the ignition off.

  • Verify that continuity at the following harness-side connector terminals between climate control unit and ground.

      • Driver-side:

    • Terminal 2B(12-pin, COLD motor drive signal)

    • Terminal 2D (12-pin, HOT motor drive signal)

      Passenger-side:

    • Terminal 2H (12-pin, COLD motor drive signal)

    • Terminal 2F (12-pin, HOT motor drive signal)

  • Is there continuity?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to ground.

Go to Step 20.

No

Go to the next step.

15

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

  • Air mix actuator connectors disconnected.

  • Switch the ignition off.

  • Verify that continuity at the following harness-side connector terminals between climate control unit and each air mix actuator.

    Driver-side air mix actuator:

  • Terminal C—climate control unit terminal 2B (12-pin, COLD motor drive signal)

  • Terminal B—climate control unit terminal 2D (12-pin, HOT motor drive signal)

    Passenger-side air mix actuator:

  • Terminal B—climate control unit terminal 2H (12-pin, COLD motor drive signal)

  • Terminal C—climate control unit terminal 2F (12-pin, HOT motor drive signal)

  • Is there continuity?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between climate control unit terminal and air mix actuator terminal.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness.

Go to Step 20.

16

 INSPECT AIR MIX ACTUATOR

Yes

Go to the next step.

No

Replace the suspected side air mix actuator.

Then go to 20. (See AIR MIX ACTUATOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)

17

 INSPECT AIR MIX LINK

  • Inspect air mix links for each-side.

    • Is grease on link?

    • Are links securely and properly installed?

    • Are links free of obstructions and hindrances?

  • Are the above items normal?

Yes

Go to the next step.

No

Apply grease to links.

If any links are damaged. Replace malfunctioning part.

Then go to Step 20.

18

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

  • Inspect A/C unit and each-side air mix door.

    • Is door free of obstructions and damage?

    • Are doors securely and properly installed?

  • Are the above items normal?

Yes

Go to the next step.

No

Remove the obstruction, or install door in proper position.

If any door are cracked, replace them.

Then go to the next step.

19

 INSPECT HEATER LINES

  • Inspect heater lines for the following:

    • Is heater piping free of damage and cracks?

    • Are heater piping connections free of engine coolant leakage?

    • Are heater piping installation points on A/C unit free of engine coolant leakage?

  • Are the above items normal?

Yes

Replace the climate control unit.

Then go to the next step.

(See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)

No

If heater piping connections are loose, tighten the connections to the specified torque.

Repair or replace heater piping.

Then go to the next step.

20

 VERIFY THAT MALFUNCTION SYMPTOM DOES NOT RECUR AFTER REPAIR

  • Does the unit operate at every temperature setting?

Yes

Troubleshooting completed.

Explain repairs to customer.

No

Recheck malfunction symptoms, then repeat from Step1 if the malfunction recurs.



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