NO.2 AMOUNT OF AIR BLOWN FROM FRONT VENTS DOES NOT CHANGE

id070300801600

2 | Amount of air blown from front vents does not change.
DESCRIPTION | • Malfunction in front blower system • Amount of air blown front vents does not change when switching front climate control unit airflow control dial.
POSSIBLE CAUSE | • Front A/C unit malfunction • Front blower motor malfunction • Malfunction in front power MOS FET system • Front climate control unit malfunction

• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while doing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions. If there is a problem, inspect to make sure connectors, terminals and wiring harness are connected correctly and undamaged.

Diagnostic procedure

STEP | INSPECTION | ACTION
--- | --- | ---
1 | INSPECT HEATER 50 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 • Turn the ignition switch to the ON position. • Turn the fan switch to ON position. • Recirculate air inside the vehicle. • Does the front blower motor operate normal speed? | Yes | Go to the next step.
No | Go to Step 4.
3 | INSPECT FRONT A/C UNIT INTAKE VENT • Is front 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 FRONT BLOWER RELAY SYSTEM OR FRONT POWER MOS FET SYSTEM • Turn the ignition switch to ON position. • Turn the fan switch to OFF position. • Measure the voltage at the following front 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 (OPEN CIRCUIT BETWEEN FUSE BLOCK AND FRONT BLOWER RELAY) OR ELSEWHERE • Measure the voltage at the following front blower relay terminals. ― Terminal B (IG2 signal) ― Terminal E (B+ signal) • Is the voltage approx. 12 V? | Yes | Go to the next step.
No | Repair the wiring harness between the front blower relay and A/C 7.5A HEATER 50 A fuse, then go to Step 15.
6* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN CIRCUIT BETWEEN FRONT BLOWER RELAY AND GROUND) OR ELSEWHERE • Measure the voltage at the following front blower relay terminal. ― Terminal D (GND signal) • Is the voltage approx. 0 V? | Yes | Go to the next step.
No | Repair the wiring harness between the front blower relay and ground, then go to Step 15.
7* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN OR SHORT CIRCUIT BETWEEN FRONT BLOWER RELAY AND FRONT BLOWER MOTOR) OR BLOWER RELAY • Measure the voltage at the following front blower relay terminal. ― Terminal A (blower motor operation signal) • Is the voltage approx. 12 V? | Yes | Repair the wiring harness between the front blower relay and blower motor, then go to Step 15.
No | Replace the front 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 front blower motor, then go to Step 15.
9* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN OR SHORT CIRCUIT BETWEEN FRONT BLOWER MOTOR AND FRONT POWER MOS FET) OR ELSEWHERE • Measure the voltage at the following terminal of front power MOS FET. ― Terminal A (blower motor operation signal) • Is voltage approx. 12 V? | Yes | Go to the next step.
No | Repair the wiring harness between the front blower motor and front power MOS FET, then go to Step 15.
10* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN OR SHORT CIRCUIT BETWEEN FRONT POWER MOS FET AND GROUND) OR ELSEWHERE • Measure the voltage at the following front power MOS FET terminal. ― Terminal E (blower motor operation signal) • Is the voltage approx. 0 V? | Yes | Go to the next step.
No | Repair the wiring harness between the front power MOS FET and ground, then go to Step 15.
11 | INSPECT FRONT A/C UNIT • Inspect the fan for following:. ― 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 front A/C unit case, then go to Step 15.
12* | INSPECT TO SEE WHETHER MALFUNCTION IS IN FRONT POWER MOS FET OR ELSEWHERE • Disconnect front power MOS FET connector. • Turn the fun switch to 1st position from off. • Measure the voltage at the following front power MOS FET terminal. ― Terminal B (blower motor control signal) • Is voltage approx. 10 V? | Yes | Replace the front power MOS FET, then go to Step 15.
No | Go to the next step.
13* | INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (OPEN CIRCUIT BETWEEN FRONT POWER MOS FET AND FRONT CLIMATE CONTROL UNIT) OR ELSEWHERE • Turn the ignition switch to the OFF position. • Disconnect front climate control unit connector. • Inspect for continuity at the following terminals between the front power MOS FET and front climate control unit. ― Terminal F—1P (blower motor control signal) ― Terminal B—1N (blower motor feedback signal) • Is there continuity? | Yes | Go to the next step.
No | Repair the wiring harness between the front 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 FRONT POWER MOS FET AND FRONT CLIMATE CONTROL UNIT) • Inspect for continuity at the following terminal between the power MOS FET and ground. ― Terminal D (blower motor control signal)—ground • Is there continuity? | Yes | Repair the wiring harness between the front power MOS FET and ground, then go to the next step.
No | Replace the front climate control unit, then go to the next step.
15 | VERIFY 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.