Automatic Temperature Control (ATC) System

The Automatic Temperature Control (ATC) system provides automatic regulation of the vehicles interior temperature. The operator selects "set temperature", on which the regulation is based, regardless of the outside temperature changes. This is done by utilizing a microcomputer, also referred to as the automatic amplifier, which receives input signals from several sensors. The automatic amplifier uses these input signals (including the set temperature) to automatically control the ATC system's outlet air volume, air temperature, air distribution, bi-level door position and rear vent door position.

Air mix door control (Automatic temperature control)
The air mix door is automatically controlled so that in-vehicle
temperature is maintained at a predetermined value by: The temperature setting, ambient temperature, in-vehicle temperature, intake air temperature and amount of sunload.

Fan speed control
Blower speed is automatically controlled based on temperature setting, ambient temperature, in-vehicle temperature, intake air temperature, amount of sunload and air mix door position.
With FAN switch set to "AUTO," the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flowing.

Intake door control
The intake doors are automatically controlled by: The temperature setting, ambient temperature, in-vehicle temperature, intake air temperature, amount of sunload and ON-OFF operation of the compressor.

Outlet door control
The outlet door is automatically controlled by: The temperature setting, ambient temperature, in-vehicle temperature, intake air temperature and amount of sunload.

Magnet clutch control
The ECM (ECCS control module) controls compressor operation using input signals from the throttle position sensor and auto amplifier.

Self-diagnostic system
The self-diagnostic system is built into the auto amplifier (BCM) to quickly locate the cause of problems.