NO.2 AMOUNT OF AIR BLOWN FROM VENTS DOES NOT CHANGE [MANUAL AIR CONDITIONER]

id0703c2800500

2 | Amount of air blown from vents does not change.
DESCRIPTION | • Malfunction in blower system.
POSSIBLE CAUSE | • Malfunction in A/C unit • Malfunction in blower motor • Malfunction in power MOS FET system • 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 HEATER 40 A FUSE • Inspect HEATER 40 A fuse. • Is it okay? | Yes | Go to the next step.
No | Replace fuse, then go to Step 15. If 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. • Turn the fan switch to ON position. • Recirculate air inside vehicle. • Does blower fan rotate smoothly? | Yes | Go to Step 4.
No | Go to the next step.
3 | INSPECT AIR DIST UNIT INTAKE VENT • Is intake vent of air dist unit clogged? | Yes | Remove obstruction, then go to Step 15.
No | Inspect if there are any obstruction in passage between air dist unit to A/C unit, 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. • Turn the fan switch to OFF position. • Test voltage at the following terminal of blower motor. ― 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 • Test voltage at the following terminal of blower relay. ― Terminal E (IG2 signal) ― Terminal C (B+ signal) • Is voltage approx. 12 V? | Yes | Go to the next step.
No | Repair wiring harness between 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 • Test voltage at the following terminal of blower relay. ― Terminal A (GND signal) • Is voltage approx. 0 V? | Yes | Go to the next step.
No | Repair wiring harness between 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 • Test voltage at the following terminal of blower relay. ― Terminal D (blower motor operation signal) • Is voltage approx. 12 V? | Yes | Repair wiring harness between blower relay and blower motor, then go to Step 15.
No | Replace blower relay, then go to Step 15.
8* | INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER MOTOR OR ELSEWHERE • Test voltage at the following terminal of blower motor. ― Terminal B (blower motor operation signal) • Is voltage approx. 12 V? | Yes | Go to the next step.
No | Inspect 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 • Test 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 wiring harness between 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 • Test voltage at the following terminal of power MOS FET. ― Terminal D (power MOS FET GND) • Is voltage approx. 0 V? | Yes | Go to the next step.
No | Repair wiring harness between power MOS FET and ground, then go to Step 15.
11 | INSPECT A/C UNIT • Inspect fan in A/C unit. ― Is fan free of interference with A/C unit case? ― Is fan free of foreign material and obstruction? • Is fan okay? | Yes | Go to the next step.
No | Remove obstruction, repair or replace 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. • Turn the fan switch to 1st position from off. • Test voltage at the following terminal of power MOS FET. ― Terminal B (blower motor control signal) • Is voltage approx. 10 V? | Yes | Replace power MOS FET, then go to Step 15. (See POWER METAL OXIDE SEMICONDUCTOR FIELD EFFECT TRANSISTOR (POWER MOS FET) REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)
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 power MOS FET and climate control unit. ― Terminal B—E (20-pin, blower motor feedback signal) ― Terminal A—C (20-pin, blower motor control signal) • Is there continuity? | Yes | Go to the next step.
No | Repair wiring harness between 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 BETWEEN POWER MOS FET AND CLIMATE CONTROL UNIT) • Inspect for continuity at the following terminal between power MOS FET and ground. ― Terminal A (blower motor control signal)—ground • Is there continuity? | Yes | Repair wiring harness between power MOS FET and ground, then go to the next step.
No | Replace climate control unit, then go to the next step. (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)
15 | CONFIRM THAT MALFUNCTION SYMPTOMS DO 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 malfunction recurs.