Home

< Previous   Next >

2008 - MX-5 - HVAC

NO.5 WINDSHIELD FOGGED



5

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.

POSSIBLE CAUSE

  • Climate control unit (B+ signal) system malfunction

  • Air intake actuator malfunction

  • Climate control unit (RECIRCULATE, FRESH signal) system malfunction

  • Malfunction in A/C unit air intake doors


Diagnostic procedure

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 the 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 the 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 the 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 (20-pin).

  • Turn ignition switch to ON position.

  • Test voltage at climate control unit connector terminal B (B+ signal).

  • Is voltage approx. 12 V?

Yes

Go to the 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 H (Ground).

  • Is voltage approx. 0V?

Yes

Go to the next step.

No

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

6

VERIFY WHETHER MALFUNCTION IS IN A/C UNIT AIR INTAKE DOOR OR ELSEWHERE

  • Turn ignition switch to LOCK position.

  • Connect climate control unit connector (20-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 the next step.

No

Go to Step 12.

7

INSPECT AIR INTAKE ACTUATOR

  • Inspect air intake actuator.

  • Is it okay?

Yes

Go to the next step.

No

Replace air intake actuator, go to Step 14. (See AIR INTAKE ACTUATOR REMOVAL/INSTALLATION.)

8

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

  • Test voltage at climate control unit connector (20-pin) terminals G and I.

  • Is it okay?

Yes

Go to the next step.

No

Replace climate control unit, then go to Step 14. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)

*9

INSPECT WIRING HARNESS BETWEEN CLIMATE CONTROL UNIT AND AIR INTAKE ACTUATOR FOR CONTINUITY

  • Turn ignition switch to LOCK position.

  • Is there continuity between following climate control unit connector (20-pin) terminal and air intake actuator connector terminal?

    • Terminal A —Terminal G (ACTR POWER)

    • Terminal C —Terminal I (ACTR SIGNAL)

Yes

Go to the next step.

No

Repair wiring harness between climate control unit and air intake actuator, then go to Step 14.

*10

INSPECT WIRING HARNESS BETWEEN CLIMATE CONTROL UNIT AND AIR INTAKE ACTUATOR FOR SHORT TO GROUND

  • Is there continuity between following climate control unit connector (20-pin) terminal and ground?

    • Terminal G (ACTR POWER)

    • Terminal I (ACTR SIGNAL)

Yes

Repair wiring harness between climate control unit and air intake actuator, then go to Step 14.

No

Go to the next step.

*11

INSPECT WIRING HARNESS BETWEEN CLIMATE CONTROL UNIT AND AIR INTAKE ACTUATOR FOR SHORT TO B+

  • Turn ignition switch to ON position

  • Test voltage at following climate control unit connector (20-pin) terminal.

    • Terminal G (ACTR POWER)

    • Terminal I (ACTR SIGNAL)

  • Is voltage approx. 12 V?

Yes

Repair wiring harness between climate control unit and air intake actuator, then go to Step 14.

No

Replace climate control unit, then go to Step 14. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)

12

INSPECT A/C UNIT AIR INTAKE DOOR

  • Is there any foreign material or obstruction in A/C unit air intake door?

Yes

Remove obstruction, then go to Step 14.

No

Go to the next step.

13

VERIFY THAT A/C UNIT AIR INTAKE DOOR IS POSITIONED SECURELY AND PROPERLY

  • Is A/C unit air intake door securely and properly positioned?

Yes

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

No

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

14

VERIFY THAT MALFUNCTION SYMPTOM OCCURS AFTER REPAIR

  • Does malfunction disappear?

Yes

Troubleshooting completed.

Explain repairs to customer.

No

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




< Previous   Next >
Back to Top
© 2009 Mazda North American Operations, U.S.A.