Automatic Operation

WARNING: This page is about a different car, the 2007 Cadillac DTS. 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 actuator.

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 60 or 90 degrees.
The mode knob must be in the AUTO position.

Once the desired temperature is reached, the blower motor, mode, recirculation and temperature actuators will automatically adjust to maintain the temperature selected. The HVAC control module performs the following functions to maintain the desired air temperature:

Regulate blower motor speed
Position the air temperature actuator
Position the mode actuator
Position the recirculation actuator
Request A/C operation

When the warmest setting 90°F is selected in automatic operation, the blower speed will increase gradually, to the maximum speed. Temperature actuators will be in full heat position, mode actuators will be in floor position while maintaining 90°F temperature setting. When normal operating temperature is reached, the blower will stay on high speed and the air temperature actuators will stay in the full heat position.

When the coldest setting 60°F is selected in automatic operation, the blower will stay on high and the air temperature actuators will stay in the full cold position. The mode actuator will remain in panel position and the recirculation actuator will remain in RECIRC position.

In cold temperatures, the automatic HVAC system will provide heat in the most efficient manner. The vehicle operator can select an extreme temperature setting, but the system will not warm the vehicle any faster. In warm temperatures, the automatic HVAC system will also provide air conditioning in the most efficient manner. Selecting an extremely cool temperature will not cool the vehicle any faster.