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
•  Blower motor malfunction (Steps 3, 4, 12)
•  Blower unit malfunction (Steps 5—9)
•  Power transistor system malfunction (Steps 10, 11, 13, 14)
•  Climate control unit malfunction (Step 15)

•  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 A/C 7.5 A FUSE
•  Inspect A/C 7.5 A fuse.
•  Is it normal?
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
CHECK TO SEE WHETHER MALFUNCTION IS IN BLOWER UNIT OR ELSEWHERE
•  Turn ignition switch to ON position.
•  Recirculate air inside vehicle.
•  Does fan in blower unit rotate smoothly?
Yes
Go to Step 4.
No
Go to the next step.
3
INSPECT BLOWER UNIT INTAKE VENT
•  Is intake vent of blower unit clogged?
Yes
Remove obstruction, then go to Step 15.
No
Inspect if there are any obstruction in passage between blower unit to A/C unit, then go to Step 15.
4*
CHECK TO SEE WHETHER MALFUNCTION IS IN BLOWER RELAY SYSTEM OR POWER TRANSISTOR SYSTEM
•  Turn ignition switch to ON 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*
CHECK 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 C (IG2 signal)
―  Terminal A (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*
CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER RELAY AND GROND) OR ELSEWHERE
•  Test voltage at the following terminal of blower relay.
―  Terminal L (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*
CHECK 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*
CHECK TO SEE WHETHER MALFUNCTION IS IN BLOWER MOTOR OR ELSEWHERE
•  Test voltage at the following terminal of blower motor.
―  Terminal A (blower motor operation signal)
•  Is voltage approx. 12 V?
Yes
Go to the next step.
No
Inspect blower motor, then go to Step 15.
(See BLOWER MOTOR INSPECTION [FULL-AUTO AIR CONDITIONER].)
9*
CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER MOTOR AND POWER TRANSISTOR) OR ELSEWHERE
•  Test voltage at the following terminal of power transistor.
―  Terminal B (blower motor operation signal)
•  Is voltage approx. 12 V?
Yes
Go to the next step.
No
Repair wiring harness between blower motor and power transistor, then go to Step 15.
10*
CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN POWER TRANSISTOR AND GROUND) OR ELSEWHERE
•  Test voltage at the following terminal of power transistor.
―  Terminal A (blower motor operation signal)
•  Is voltage approx. 0 V?
Yes
Go to the next step.
No
Repair wiring harness between power transistor and ground, then go to Step 15.
11
INSPECT BLOWER UNIT
•  Inspect fan in blower unit.
―  Is fan free of interference with blower unit case?
―  Is fan free of foreign material and obstruction?
•  Is voltage approx. 0 V?
Yes
Go to the next step.
No
Remove obstruction, repair or replace fan and blower unit case, then go to Step 15.
12*
CHECK TO SEE WHETHER MALFUNCTION IS IN POWER TRANSISTOR OR ELSEWHERE
•  Disconnect power transistor connector.
•  Test voltage at the following terminal of power transistor.
―  Terminal B (blower motor control signal)
•  Is voltage approx. 10 V?
Yes
Replace power transistor, then go to Step 15.
No
Go to the next step.
13*
CHECK TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN POWER TRANSISTOR AND A/C AMPLIFIER) OR ELSEWHERE
•  Turn ignition switch to LOCK position.
•  Disconnect A/C amplifier connector.
•  Inspect for continuity at the following terminals between power transistor and A/C amplifier.
―  Terminal D—1A (24-pin, blower motor control signal)
―  Terminal C—1B (24-pin, blower motor feedback signal)
•  Is there continuity?
Yes
Go to the next step.
No
Repair wiring harness between power transistor and A/C amplifier, then go to Step 15.
14*
CHECK TO SEE WHETHER MALFUNCTION IS IN A/C AMPLIFIER OR WIRING HARNESS (SHORT TO GROUND BETWEEN POWER TRANSISTOR AND A/C AMPLIFIER) OR ELSEWHERE
•  Inspect for continuity at the following terminal between power transistor and ground.
―  Terminal A (24-pin, blower motor control signal)—ground
•  Is there continuity?
Yes
Repair wiring harness between power transistor and ground, then go to the next step.
No
Replace A/C amplifier, then go to the next step.
15
VERIFY THAT MALFUNCTION SYMPTOM OCCURS 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.