Air Mix Door Motor Circuit

TROUBLE DIAGNOSIS


Air Mix Door Motor Circuit


SYMPTOM:
- Discharge air temperature does not change.
- Air mix door motor does not operate.

INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE INCREASE
1. Turn the temperature control dial clockwise.
2. Check for hot air at discharge air outlets.
- GO TO 2.
2.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE DECREASE
1. Turn the temperature control dial counterclockwise.
2. Check for cold air at discharge air outlets.
Can a symptom be duplicated?
YES - GO TO 4.
NO - GO TO 3.
3.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Operational Check.
Can a symptom be duplicated?
YES - How To Perform Trouble Diagnosis For Quick And Accurate Repair.
NO - System OK.
4.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
- GO TO 5.
5.CHECK AIR MIX DOOR OPERATION
Check and verify air mix door mechanism for smooth operation in each mode.
OK or NG
OK - GO TO 6.
NG - Repair as necessary.
6.CHECK LAN SYSTEM CIRCUIT
Perform diagnostic procedure for the LAN system. LAN System Circuit.
OK or NG
OK - If the symptom still exists, perform a complete operational check. Operational Check. If no other symptom exists replace front air control. Service and Repair.
NG - Repair as necessary.

SYSTEM DESCRIPTION

Component Parts

Air mix door control system components are:
- Front air control
- Air mix door motor (LCU)

System Operation
The front air control receives signals from its various dials and switches. The front air control then sends air mix door, mode door and intake door motor opening angle data to the air mix door motor LCU, mode door motor LCU and intake door motor LCU.
The air mix door motor, mode door motor and intake door motor read their respective signals according to the address signal. Opening angle indication signals received from the front air control and each of the motor position sensors are compared by the LCUs in each motor with the existing decision and opening angles. Subsequently, HOT/COLD or DEFROST/VENT or FRESH/RECIRCULATION operation is selected. The new selection data is returned to the front air control.






COMPONENT DESCRIPTION

Air Mix Door Motor





The air mix door motor (1) is attached to the heater and cooling unit assembly. It rotates so that the air mix door is opened or closed to a position set by the front air control. Motor rotation is then conveyed through a shaft and the air mix door position is then fed back to the front air control by PBR built-in air mix door motor.

DIAGNOSTIC PROCEDURE
SYMPTOM: Discharge air temperature does not change.
Perform diagnostic procedure for LAN system circuit. LAN System Circuit.