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.