Diagnosis Procedure
BLOWER MOTOR
Description
SYSTEM DESCRIPTION
Component Parts
Fan speed control system components are:
- Front air control
- A/C LAN system (PBR built-in mode door motor, air mix door motors and intake door motor)
- In-vehicle sensor
- Ambient sensor
- Sunload sensor
- Intake sensor
- Fan control amp.
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calculated by the front air control based on the input from the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.
When the air flow is increased, the duty ratio of the blower fan motor's drive signal is changed at 8%/sec. to prevent a sudden increase in air flow.
In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low water temperature starting control and high passenger compartment temperature starting control are available.
Starting Fan Speed Control
Start up from COLD SOAK Condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 56�C (133�F), the blower will not operate for a short period of time (up to 150 seconds). The exact start delay time varies depending on the ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described above. After this delay, the blower will operate at low speed until the engine coolant temperature rises above 56 °C (133�F), at which time the blower speed will increase to the objective speed.
Start up from usual or HOT SOAK Condition (Automatic mode)
The blower will begin operation momentarily after the AUTO switch is pressed. The blower speed will gradually rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective blower speed).
Blower Speed Compensation
Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low speed. The low speed will vary depending on the sunload. During conditions of low or no sunload, the blower speed is at duty ratio of 25%. During high sunload conditions, the front air control will raise the blower speed
(duty ratio of 49%).
Blower Speed Control Specification
BLOWER MOTOR
Diagnosis Procedure
Regarding Wiring Diagram information, refer to Coupe or Sedan.
SYMPTOM: Blower motor operation is malfunctioning.
DIAGNOSIS PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning under starting blower speed control.
1.PERFORM SELF-DIAGNOSIS STEP-4
Perform self-diagnosis STEP-4. Refer to Diagnosis Description.
Does blower motor speed change according to each code No.?
YES - Inspection End.
NO - GO TO 2
2.CHECK POWER SUPPLY FOR BLOWER MOTOR
1. Turn ignition switch OFF.
2. Disconnect blower motor connector.
3. Turn ignition switch ON.
4. Check voltage between blower motor harness connector M31 terminal 4 and ground.
4 - Ground : Battery voltage
Is the inspection result normal?
YES - GO TO 3
NO - GO TO 6
3.CHECK BODY GROUND CIRCUIT FOR BLOWER MOTOR
1. Press ignition switch OFF.
2. Check continuity between blower motor harness connector M31 terminal 1 and ground.
Is the inspection result normal?
YES - GO TO 4
NO - Repair harness or connector.
4.CHECK BLOWER MOTOR CONTROL CIRCUIT BETWEEN BLOWER MOTOR AND FRONT AIR CONTROL
1. Disconnect front air control harness connector.
2. Check continuity between blower motor harness connector M31
(A) terminal 3 and front air control harness connector M152 (B) terminal 1.
Is the inspection result normal?
YES - GO TO 5
NO - Repair harness or connector.
5.CHECK FRONT AIR CONTROL OUTPUT SIGNAL
1. Reconnect blower motor connector and front air control connector.
2. Press ignition switch ON.
3. Set MODE switch to the VENT position.
4. Check the output waveform between blower motor harness connector M31 terminal 3 and ground using an oscilloscope, while varying the fan speed from 1 to 7.
Is the inspection result normal?
YES - Replace the blower motor. Refer to Blower Unit.
NO - Replace the front air control. Refer to Service and Repair.
6.CHECK FUSE
Check 15A fuses (Nos. 21 and 22).
NOTE:
Refer to Coupe (coupe) or Sedan (sedan) for fuse location.
Is the inspection result normal?
YES - GO TO 7
NO - GO TO 12
7.CHECK POWER SUPPLY FOR FRONT BLOWER MOTOR RELAY
1. Press ignition switch OFF.
2. Disconnect fuse block (J/B) connector.
3. Press ignition switch ON.
4. Turn blower motor control dial to any speed except OFF.
5. Check voltage between fuse block (J/B) connector E6 terminal
6P and ground.
6P - Ground : Battery Voltage
Is the inspection result normal?
YES - GO TO 11
NO - GO TO 8
8.CHECK POWER SUPPLY FOR FRONT BLOWER MOTOR RELAY FOR AN OPEN
1. Press ignition switch OFF.
2. Disconnect BCM harness connector M19.
3. Check continuity between BCM harness connector M19 (A) terminal 90 and fuse block (J/B) harness connector E6 (B) terminal 6P.
Is the inspection result normal?
YES - GO TO 9
NO - Repair harness or connector.
9.CHECK BLOWER FAN SWITCH SIGNAL FOR VOLTAGE
1. Disconnect BCM harness connector M18.
2. Press ignition switch ON.
3. Check voltage between BCM harness connector M18 terminal
55 and ground.
Is the inspection result normal?
YES - Replace BCM. Refer to BCM.
NO - GO TO 10
10.CHECK BLOWER FAN SWITCH SIGNAL CIRCUIT FOR AN OPEN
1. Press ignition switch OFF.
2. Disconnect front air control harness connector.
3. Check continuity between BCM harness connector M18 (A) terminal 55 and front air control harness connector M152 (B) terminal 24.
Is the inspection result normal?
YES - Replace front air control. Refer to Service and Repair.
NO - Repair harness or connector.
11.CHECK FRONT BLOWER MOTOR RELAY GROUND
1. Press ignition switch OFF.
2. Check continuity between fuse block (J/B) harness connector
M5 terminal 7M and ground.
Is the inspection result normal?
YES - Replace front blower motor relay.
NO - Repair harness or connector.
12.REPLACE FUSES
1. Reconnect blower motor connector.
2. Replace fuses.
3. Activate the blower motor.
Does the fuse blow?
YES - GO TO 13
NO - Inspection End.
13.CHECK BLOWER MOTOR POWER SUPPLY CIRCUIT FOR SHORT
1. Turn ignition switch OFF.
2. Disconnect blower motor harness connector and front air control.
3. Check continuity between blower motor harness connector M31 terminal 4 and ground.
4 - Ground : Continuity should not exist.
Is the inspection result normal?
YES - Replace blower motor. Refer to Blower Unit.
NO - Repair harness or connector.