Automatic Operation

WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

In automatic operation, the HVAC control module will maintain the comfort level inside of the vehicle by controlling the A/C compressor clutch, the blower motor, the air temperature actuators, mode actuator and recirculation.

To place the HVAC system in Automatic mode, the following is required:

The blower motor switch must be in the AUTO position.
The air temperature switch must be in any other position other than 15°C (60°F) or 32°C (90°F).
The mode switch must be in the Auto position.
Once the desired temperature is reached, the blower motor, mode, recirculation and temperature actuators will automatically be adjusted to maintain the temperature selected. The HVAC control module performs the following functions to maintain the desired air temperature:
Monitor the following sensors:
- Inside air temperature sensor
- Ambient air temperature sensor
- Sunload sensor
Regulate blower motor speed.
Position the air temperature actuator.
Position the mode actuator.
Position the recirculation actuator.
Request A/C operation.

The automatic HVAC system will warm and cool the vehicle in the most efficient manner. Selecting either the warmest or coldest temperature will not improve the system performance. If the warmest or coldest temperature setting is selected while the HVAC system is in automatic operation, then the following will occur:

Warmest position - The blower motor speed increases to maximum speed, and the air temperature actuator is placed in the warmest position.
Coldest position -
- The blower motor speed increases to maximum speed.
- Air temperature actuator is placed in the coldest position.
- Mode actuator is placed in panel position.

Recirculation actuator is set to the recirculation position.