NO.2 AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE [FULL-AUTO AIR CONDITIONER]

id0703c1800500

2 | Amount of air blown from vents does not change.
DESCRIPTION | • Malfunction in blower system
POSSIBLE CAUSE | • A/C unit malfunction • Blower motor malfunction • Malfunction in power MOS FET system • Climate control unit malfunction

• 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, inspect make sure connectors, terminals and wiring harnesses are connected correctly and undamaged.

Diagnostic procedure

STEP | INSPECTION | ACTION
--- | --- | ---
1 | INSPECT HEATER 40 A FUSE • Inspect the HEATER 40 A fuse. • Is it normal? | Yes | Go to the next step.
No | Replace the fuse, then go to Step 15. If the fuse burns out immediately, go to the next step.
2 | INSPECT TO SEE WHETHER MALFUNCTION IS IN A/C UNIT OR ELSEWHERE • Switch the ignition to ON. • Recirculate air inside the vehicle. • Does the blower motor rotate smoothly? | Yes | Go to Step 4.
No | Go to the next step.
3 | INSPECT A/C UNIT INTAKE VENT • Is A/C unit intake vent clogged? | Yes | Remove obstruction, then go to Step 15.
No | Inspect if there are any obstruction in the A/C unit passage, then go to Step 15.
4* | INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER RELAY SYSTEM OR POWER MOS FET SYSTEM • Switch the ignition to ON. • Measure the voltage at the following blower motor terminal. ― Terminal B (blower motor operation signal) • Is voltage approx. 12 V? | Yes | Go to Step 8.
No | Go to the next step.
5* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN FUSE BLOCK AND BLOWER RELAY) OR ELSEWHERE • Measure the voltage at the following blower relay terminals. ― Terminal E (IG2 signal) ― Terminal C (B+ signal) • Is the voltage approx. 12 V? | Yes | Go to the next step.
No | Repair the wiring harness between the blower relay and HEATER 40 A fuse, then go to Step 15.
6* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER RELAY AND GROUND) OR ELSEWHERE • Measure the voltage at the following blower relay terminal. ― Terminal A (GND signal) • Is the voltage approx. 0 V? | Yes | Go to the next step.
No | Repair the wiring harness between the blower relay and ground, then go to Step 15.
7* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER RELAY AND BLOWER MOTOR) OR BLOWER RELAY • Measure the voltage at the following blower relay terminal. ― Terminal D (blower motor operation signal) • Is the voltage approx. 12 V? | Yes | Repair the wiring harness between the blower relay and blower motor, then go to Step 15.
No | Replace the blower relay, then go to Step 15.
8* | INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER MOTOR OR ELSEWHERE • Measure the voltage at the following blower motor terminal. ― Terminal B (blower motor operation signal) • Is the voltage approx. 12 V? | Yes | Go to the next step.
No | Inspect the blower motor, then go to Step 15.
9* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER MOTOR AND POWER MOS FET) OR ELSEWHERE • Measure the voltage at the following terminal of power MOS FET. ― Terminal C (blower motor operation signal) • Is voltage approx. 12 V? | Yes | Go to the next step.
No | Repair the wiring harness between the blower motor and power MOS FET, then go to Step 15.
10* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN POWER MOS FET AND GROUND) OR ELSEWHERE • Measure the voltage at the following power MOS FET terminal. ― Terminal D (power MOS FET ground) • Is the voltage approx. 0 V? | Yes | Go to the next step.
No | Repair the wiring harness between the power MOS FET and ground, then go to Step 15.
11 | INSPECT A/C UNIT • Inspect the fan in A/C unit. ― Is the fan free of interference with the A/C unit case? ― Is the fan free of foreign material and obstruction? • Is the fan normal? | Yes | Go to the next step.
No | Remove obstruction, repair or replace the fan and A/C unit case, then go to Step 15.
12* | INSPECT TO SEE WHETHER MALFUNCTION IS IN POWER MOS FET OR ELSEWHERE • Disconnect power MOS FET connector. • Measure the voltage at the following power MOS FET terminal. ― Terminal B (blower motor control signal) • Is voltage approx. 10 V? | Yes | Replace the power MOS FET, then go to Step 15.
No | Go to the next step.
13* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN POWER MOS FET AND CLIMATE CONTROL UNIT) OR ELSEWHERE • Switch the ignition to off. • Disconnect climate control unit connector. • Inspect for continuity at the following terminals between the power MOS FET and climate control unit. ― Terminal A—C (20 pin, blower motor control signal) ― Terminal B—E (20 pin, blower motor feedback signal) • Is there continuity? | Yes | Go to the next step.
No | Repair the wiring harness between the power MOS FET and climate control unit, then go to Step 15.
14* | INSPECT TO SEE WHETHER MALFUNCTION IS IN CLIMATE CONTROL UNIT OR WIRING HARNESS (SHORT TO GROUND IN WIRING HARNESS BETWEEN POWER MOS FET AND CLIMATE CONTROL UNIT) • Inspect for continuity at the following terminal between the power MOS FET and ground. ― Terminal A (blower motor control signal)—ground • Is there continuity? | Yes | Repair the wiring harness between the power MOS FET and ground, then go to the next step.
No | Replace the climate control unit, then go to the next step.
15 | CONFIRM THAT MALFUNCTION SYMPTOM DOES NOT RECUR AFTER REPAIR • Is air discharged from vent? | Yes | Troubleshooting completed. Explain repairs to customer.
No | Recheck malfunction symptoms, then repeat from Step 1 if the malfunction recurs.