NO.9 NO COOL AIR FROM FRONT/REAR VENTS

id070300901400

9 | No cool air from front/rear vents
DESCRIPTION | • Malfunction in A/C compressor control system • Magnetic clutch does not operate when the A/C system is turned ON.
POSSIBLE CAUSE | • Malfunction in PCM A/C cut control system • Malfunction in refrigerant pressure sensor • 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 • Malfunction in climate control unit

• 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

STEP | INSPECTION | ACTION
--- | --- | ---
1 | INSPECT AIR FLOW FROM VENTS • 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 REFRIGERANT PRESSURE SENSOR OR REFRIGERANT AMOUNT • Inspect refrigerant pressure sensor. (See REFRIGERANT PRESSURE SENSOR INSPECTION.) • Is it okay? | Yes | Go to the next step.
No | Replace refrigerant pressure sensor, then go to Step 12. (See REFRIGERANT PRESSURE SENSOR REMOVAL/INSTALLATION.)
5 | INSPECT TO SEE WHETHER MALFUNCTION (SHORT CIRCUIT) 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 | Repair or replace short circuit, then go to the next step.
No | Go to Step 7.
6* | INSPECT TO SEE WHETHER MALFUNCTION (OPEN OR SHORT CIRCUIT) IS IN PCM OR WIRING HARNESS (BETWEEN A/C RELAY AND PCM) • Test voltage at the A/C relay control signal terminal of PCM. • Is voltage approx. 12 V? | Yes | Inspect PCM, then go to Step 12.
No | Repair wiring harness between A/C relay and PCM, then go to Step 12.
7* | INSPECT TO SEE WHETHER MALFUNCTION IS IN MAGNETIC CLUTCH OR ELSEWHERE • Test voltage at the following terminal of magnetic clutch thermal protector. ― Terminal B (magnetic clutch operation signal) • Is voltage approx. 12 V? | Yes | Inspect magnetic clutch, then go to Step 12.
No | Go to the next step.
8 | INSPECT FUSE • Are A/C relay power supply fuses okay? | Yes | Go to the next step.
No | Replace fuse, then go to Step 12. If fuse burns out immediately, go to the next step.
9 | INSPECT WIRING HARNESS BETWEEN FUSE BLOCK AND A/C RELAY FOR LACK OF CONTINUITY • Test voltages at following terminals of A/C relay. ― Terminal A (A/C relay control signal) ― Terminal C (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 12.
10 | 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 12.
No | Replace A/C relay, then go to Step 12.
11 | 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.
12 | VERIFY REPAIR • Does cool air blow out from front/rear vents? (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. • If the malfunction remines, replace the climate control unit. (See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)