HVAC Control Module

The HVAC control module is a non-class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive and ignition 1 voltage circuits provide power to the control module. The control module supports the following features:

Auxiliary HVAC Control Module (part of rear seat audio controls) The auxiliary HVAC control module is located as an integral part of the rear seat audio controls located in the rear center console. The system can be controlled from both the front and rear controls. To activate the rear HVAC system press the AUX button on the front climate controls, an indicator will be lit. Pressing the AUX button once will set the rear HVAC into mimic mode. In this mode the airflow in the rear will be approximately the same direction, temperature, and fan speed as the front. Pressing the front climate control AUX button again will turn the rear system and the indicator off. If the rear controls are adjusted, the rear control will enter a rear independent state. Airflow in the rear will then be according to the settings of the rear HVAC controls. The rear system can be turned off by pressing the AUX button on the front HVAC climate control and the status light will turn off. If the front AUX button is off then the rear climate control system is off. A GM LAN device that interfaces between the rear seat occupants and the auxiliary HVAC system to maintain auxiliary air temperature and auxiliary air distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all auxiliary HVAC DTCs and settings will be erased from KAM. The auxiliary HVAC control module will perform a recalibration of the electric actuators when commanded with a scan tool or if KAM is lost. This will ensure the actuators are moving with in the calibrated range. During this calibration process the auxiliary blower motor will be disabled for up to 3 minutes. With this HVAC control head a automatic operation can be achieved by pressing the plus or minus temperature buttons to increase or decrease cabin temperature. The temp display on the rear HVAC head will display the temp setting increasing or decreasing. These climate control functions will only display in rear independent mode when the rear controls are being used. Manual controls of the rear climate control consist of: Fan to decrease or increase fan speed. The up arrow fan control will turn on the rear HVAC control in manual mode. The down arrow fan control will turn off the rear HVAC manual mode. The increase and decrease temperature buttons adjust the rear flow of air temperature to the rear occupants. The mode button will manually change the direction of air flow in your vehicle. Multiple presses will cycle through the rear air delivery selections until the desired mode of choice is displayed.

Auxiliary HVAC Control Module (three knobs located in rear headliner) This type of rear climate control consists of three knobs located in the rear headliner. This rear control system can be controlled form both the front and rear HVAC. To turn on this rear system, press the front HVAC controls AUX button, an indicator on the AUX button will be lit. To activate the rear HVAC system press the AUX button on the front climate controls, an indicator will be lit. Pressing the AUX button once will set the rear HVAC into mimic mode. In this mode the airflow in the rear will be approximately the same direction, temperature, and fan speed as the front. Pressing the front climate control AUX button again will turn the rear system and the indicator off. If the rear controls are adjusted, the rear control will enter a rear independent state. Airflow in the rear will then be according to the settings of the rear HVAC controls. The rear system can be turned off by pressing the AUX button on the front HVAC climate control and the status light will turn off. If the front AUX button is off then the rear climate control system is off. The three rear control knobs starting from the left, fan control turning clockwise or counter clockwise. Turning the fan control knob all the way counter clockwise turns the rear climate control off. Center knob controls the rear temperature of the air flowing through the rear passenger compartment. A clockwise turn into the red dial area produces warmer air, a counter clockwise turn into the blue dial area produces cooler air temperatures. The right knob controls air delivery with choices of VENT air directed through headliner outlets. Bi-Level air is delivered through the floor outlets as well as the headliner outlets. Floor air is directed through floor outlets, the location of the floor outlets is directly behind the second row seats.