Automatic Operation: Notes

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. 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 Auto switch must be activated
The air temperature switch must be in any other position other than full hot or full cold 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
Lower Left Air Temperature Sensor
Lower Right Air Temperature Sensor
Upper Left Air Temperature Sensor
Upper Right Air Temperature Sensor
Regulate blower motor speed.
Position the air temperature actuator.
Position the mode actuator.
Position the recirculation actuator.
Request A/C operation.

In automatic operation, the auxiliary HVAC control module will maintain the comfort level inside of the vehicle by controlling the auxiliary blower motor, the auxiliary air temperature actuator and the auxiliary mode actuator.

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

The auxiliary blower motor switch on the auxiliary HVAC control assembly must be in the Auto position.
The auxiliary mode switch on the auxiliary HVAC control assembly must be in the Auto position.
The auxiliary air temperature switch must be in any other position other than full hot or full cold position.

Once the desired temperature is reached, the auxiliary blower motor, auxiliary mode and auxiliary temperature actuator will automatically be adjusted to maintain the temperature selected. The auxiliary HVAC control module performs the following functions to maintain the desired air temperature:

Upper Air Temperature Sensor - Auxiliary
Lower Air Temperature Sensor - Auxiliary
Regulate auxiliary blower motor speed
Position the auxiliary air temperature actuator
Position the auxiliary mode actuator