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 normally.

INSPECTION FLOW






SYSTEM DESCRIPTION

Component Parts

Air mix door control system components are:
- Unified meter and A/C amp.
- Air mix door motor (LCU)
- A/C LAN system (PBR built-in mode door motor, upper ventilator door motor, air mix door motor and intake door motor)
- In-vehicle sensor
- Ambient sensor
- Sunload sensor
- Intake sensor

System Operation
- The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp. sends air mix door, mode door, upper ventilator door and intake door opening angle data to the air mix door motor LCUs, mode door motor LCUs, upper ventilator door motor LCU and intake door motor LCU.
- The air mix door motors, mode door motors, upper ventilator door motor and intake door motor read their respective signals according to the address signal. Opening angle indication signals received from the unified meter and A/C amp. and each of the motor position sensors are compared by the LCUs in each door motor with the existing decision and opening angles.
- Subsequently, HOT/COLD, DEF/VENT, OPEN/SHUT and FRE/REC operation is selected. The new selection data are returned to the unified meter and A/C amp.





Air Mix Door Control Specification
When ignition switch is ON, unified meter and A/C amp. continuously and automatically controls temperatures regardless of air conditioner operational condition. When setting a target temperature with temperature control switch, unified meter and A/C amp. corrects the set temperature and decides a target air mix door opening angle. Unified meter and A/C amp. controls air mix door according to the target air mix door opening angle and current air mix door opening angle for keeping an optimum air mix door opening angle. When a temperature is set at 18�C (60�F), air mix door is fixed at full cold, and when a temperature is set at 32�C (90�F), it is set at full hot.






COMPONENT DESCRIPTION

Air Mix Door Motor
The air mix door motors are 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 unified meter and A/C amp. Motor rotation is then conveyed through a shaft and the air mix door position feedback is then sent to the unified meter and A/C amp. by PBR built-in air mix door motor.

DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR
SYMPTOM: Discharge air temperature does not change.









Perform diagnosis procedure. Refer to LAN System Circuit.