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 unit malfunction
•  Blower motor malfunction
•  Malfunction in blower fan controller 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
If the fuse is melted:
Repair or replace wiring harness for short to GND and replace the fuse.
If the fuse is deterioration:
Replace the fuse.
Then go to Step 15.
2
INSPECT TO SEE WHETHER MALFUNCTION IS IN BLOWER UNIT OR ELSEWHERE
•  Switch the ignition ON (engine off or on).
•  Turn the airflow volume control switch to ON position.
•  Recirculate air inside the vehicle.
•  Does the blower motor rotate smoothly?
Yes
Go to the next step.
No
Go to Step 4.
3
INSPECT BLOWER UNIT INTAKE VENT
•  Is blower 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 BLOWER FAN CONTROLLER SYSTEM
•  Switch the ignition ON (engine off or on).
•  Turn the airflow volume control switch to ON position.
•  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 A (B+ signal)
―  Terminal B (B+ signal)
•  Is the voltage approx. 12 V?
Yes
Go to the next step.
No
Repair the wiring harness for lack of continuity between the blower relay 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 D (GND signal)
•  Is the voltage approx. 0 V?
Yes
Go to the next step.
No
Repair the wiring harness for lack of continuity between the blower relay and front body control module (FBCM), then go to Step 15.
7*
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER RELAY AND BLOWER FAN CONTROLLER) OR BLOWER RELAY
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following blower relay terminal.
―  Terminal C (blower motor operation signal)
•  Is the voltage approx. 12 V?
Yes
Repair the wiring harness for lack of continuity between the blower relay and blower fan controller, then go to Step 15.
No
Replace the blower relay, then go to Step 15.
8*
INSPECT BLOWER MOTOR
•  Inspect the blower motor.
(See BLOWER MOTOR INSPECTION [FULL-AUTO AIR CONDITIONER].)
•  Is the blower motor normal?
Yes
Go to the next step.
No
Replace the blower motor, then go to Step 15.
(See BLOWER MOTOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
9*
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER MOTOR AND BLOWER FAN CONTROLLER) OR ELSEWHERE
•  Measure the voltage at the following terminal of blower fan controller.
―  Terminal E (blower motor operation signal)
•  Is voltage approx. 12 V?
Yes
Go to the next step.
No
Repair the wiring harness for lack of continuity between the blower motor and blower fan controller, then go to Step 15.
10*
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER FAN CONTROLLER AND GROUND) OR ELSEWHERE
•   Measure the voltage at the following blower fan controller terminal.
―  Terminal C (GND)
•  Is the voltage approx. 0 V?
Yes
Go to the next step.
No
Repair the wiring harness for lack of continuity between the blower fan controller and ground, then go to Step 15.
11
INSPECT BLOWER UNIT
•  Inspect the fan in blower unit.
―  Is the fan free of interference with the blower 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 blower unit case, then go to Step 15.
12*
INSPECT BLOWER FAN CONTROLLER
•  Inspect the blower fan controller.
•  Is the blower fan controller normal?
Yes
Go to the next step.
No
Replace the blower fan controller, then go to Step 15.
(See BLOWER FAN CONTROLLER REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
13*
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (LACK OF CONTINUITY BETWEEN BLOWER FAN CONTROLLER AND CLIMATE CONTROL UNIT) OR ELSEWHERE
•  Switch the ignition off.
•  Disconnect climate control unit connector.
•  Inspect for continuity at the following terminals between the blower fan controller and climate control unit.
―  Terminal B—2D(blower motor speed control signal)
•  Is there continuity?
Yes
Go to the next step.
No
Repair the wiring harness for lack of continuity between the blower fan controller 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 BLOWER FAN CONTROLLER AND CLIMATE CONTROL UNIT)
•  Inspect for continuity at the following terminal between the blower fan controller and ground.
―  Terminal E (blower motor control signal)—ground
―  Terminal B (blower motor feedback signal)—ground
•  Is there continuity?
Yes
Repair the wiring harness for short to GND between the blower fan controller and ground, then go to the next step.
No
Replace the climate control unit, then go to the next step.
(See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
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.