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 25%. During high sunload conditions, the front air control. raise the blower speed (duty ratio 49%).
Check continuity between blower motor harness connector M31 terminal 1 and ground.
Is the Inspection result normal?
YES >> Reconnect blower motor harness connector and GO TO
3
NO >> Repair harness or connector. 3.CHECK BLOWER MOTOR CONTROL CIRCUIT BETWEEN BLOWER MOTOR AND FRONT AIR CONTROL
Disconnect front air control harness connector.
Check continuity between blower motor harness connector M31 (A) terminal 3 and front air control harness connector M37 (B) terminal 1.
Is the Inspection result normal?
YES >> GO TO 4
NO >> Repair harness or connector. 4.CHECK POWER SUPPLY FOR FRONT AIR CONTROL
Press ignition switch ON.
Check voltage between front air control harness connector M37 terminals 39, 19, 40 and ground.