Home

< Previous   Next >

2008 - MX-5 - HVAC

NO.7 AIR FROM VENTS NOT COLD ENOUGH



7

No cool air

DESCRIPTION

  • Magnetic clutch does not operate.

POSSIBLE CAUSE

  • Malfunction in PCM A/C cut control system

  • Malfunction in climate control unit

  • Malfunction in refrigerant pressure switch

  • Malfunction in PCM (A/C signal)

  • Malfunction in PCM (IG1 signal)

  • Malfunction in A/C compressor

  • Malfunction in A/C relay

  • Malfunction in evaporator temperature sensor


Diagnostic procedure

STEP

INSPECTION

ACTION

1

INSPECT AIR BLOW OUT

  • Does air blow out?

Yes

Go to the next step.

No

Go to Step 1 of troubleshooting indexes No.1 and 2.

2

INSPECT A/C COMPRESSOR OPERATION

  • Start engine.

  • Turn A/C switch and fan switch on.

  • Does A/C compressor operate?

Yes

Go to Step 1 of troubleshooting index No.7.

No

Go to the next step.

3

INSPECT FOR DTC IN PCM

  • Inspect for DTCs related to the PCM on-board diagnostic system.

  • Are any DTCs displayed?

Yes

Go to appropriate inspection procedure.

No

Go to the next step.

4

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

  • Does cool air blow out when terminal K of climate control unit connector (20-pin, A/C signal) is grounded?

Yes

Replace climate control unit, then go to Step 17. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)

No

Release short, then go to the next step.

5*

INSPECT TO SEE WHETHER MALFUNCTION IS IN A/C SIGNAL CIRCUIT (BETWEEN REFRIGERANT PRESSURE SWITCH AND PCM) OR ELSEWHERE

  • Test voltage at following terminal of refrigerant pressure switch.

    • Terminal D (A/C signal)

  • Is voltage approx. 12 V?

Yes

Go to Step 7.

No

Go to the next step.

6*

INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN WIRING HARNESS (BETWEEN REFRIGERANT PRESSURE SWITCH AND PCM) OR PCM

  • Test voltage at A/C signal terminal AU of PCM.

  • Is voltage approx. 12 V?

Yes

Repair wiring harness between PCM and refrigerant pressure switch, then go to Step 17.

No

Inspect PCM, then go to Step 17.

7

INSPECT TO SEE WHETHER MALFUNCTION IS IN REFRIGERANT PRESSURE SWITCH, REFRIGERANT AMOUNT, OR ELSEWHERE

  • Does cool air blow out when terminals C and D of refrigerant pressure switch connector are shorted?

Yes

Go to Step 9.

No

Go to the next step.

8*

INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (BETWEEN REFRIGERANT PRESSURE SWITCH AND CLIMATE CONTROL UNIT) OR ELSEWHERE

  • Test voltage at following terminal of climate control unit.

    • Terminal K (20-pin, A/C signal)

  • Is voltage approx. 12 V?

Yes

Go to Step 10.

No

Repair wiring harness between refrigerant pressure switch and climate control unit, then go to Step 17.

9

INSPECT TO SEE WHETHER MALFUNCTION IS IN REFRIGERANT PRESSURE SWITCH OR REFRIGERANT AMOUNT

  • Inspect refrigerant pressure switch.

  • Is it okay?

Yes

If refrigerant amount is empty, replace condenser, apply vaccum to refrigerant line for more than 30 min using vacuum pump, and add refrigerant to specified level, then go to Step 17. (See CONDENSER REMOVAL/INSTALLATION.)

No

Replace refrigerant pressure switch, then go to Step 17. (See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION.)

10

INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN A/C CONTROL SIGNAL CIRCUIT (BETWEEN A/C RELAY AND PCM) OR ELSEWHERE

  • Does cool air blow out when terminal E of A/C relay connector (A/C control signal) is grounded?

Yes

Release short, then go to the next step.

No

Go to Step 12.

11*

INSPECT TO SEE WHETHER MALFUNCTION (LACK OF CONTINUITY) IS IN PCM OR WIRING HARNESS (BETWEEN A/C RELAY AND PCM)

  • Test voltage at the A/C relay control signal terminal I of PCM.

  • Is voltage approx. 12 V?

Yes

Inspect PCM, then go to Step 17.

No

Repair wiring harness between A/C relay and PCM, then go to Step 17.

12*

INSPECT TO SEE WHETHER MALFUNCTION IS IN MAGNETIC CLUTCH OR ELSEWHERE

  • Test voltage at the following terminal of magnetic clutch thermal protector.

    • Terminal A (magnetic clutch operation signal)

  • Is voltage approx. 12 V?

Yes

Inspect magnetic clutch, then go to Step 17.

No

Go to the next step.

13

INSPECT FUSE

  • Are A/C relay power supply fuses okay?

Yes

Go to the next step.

No

Replace fuse, then go to Step 17. If fuse burns out immediately, go to the next step.

14

INSPECT WIRING HARNESS BETWEEN FUSE BLOCK AND A/C RELAY FOR LACK OF CONTINUITY

  • Test voltages at following terminals of A/C relay.

    • Terminal C (A/C relay control signal)

    • Terminal A (A/C control signal)

  • Are voltages approx. 12 V?

Yes

Go to the next step.

No

Repair wiring harness between fuse block and A/C relay, then go to Step 17.

15

INSPECT TO SEE WHETHER MALFUNCTION IS IN A/C RELAY OR WIRING HARNESS (BETWEEN A/C RELAY AND MAGNETIC CLUTCH) AND EVAPORATOR TEMPERATURE SENSOR

  • Test voltage at the following terminal of A/C relay.

    • Terminal D (magnetic clutch operation signal)

  • Is voltage approx. 12 V?

Yes

Inspect wiring harness between A/C relay and magnetic clutch.

  • If above wiring harness is OK, go to the next step.

  • If above wiring harness malfunctions, repair wiring harness, then go to Step 17.

No

Replace A/C relay, then go to Step 17.

16

INSPECT EVAPORATOR TEMPERATURE SENSOR

  • Inspect evaporator temperature sensor.

  • Is it okay?

Yes

Go to the next step.

No

Replace evaporator temperature sensor, then go to the next step.

17

CONFIRM THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR

  • Does cool air blow out? (Are the results of refrigerant system performance test okay?)

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.