K 1500 Suburban 4WD V8-5.3L VIN Z Flex Fuel (2003)
Control Assembly: Description and Operation
HVAC System - Automatic
AIR DELIVERY
HVAC Control Module
The HVAC control module is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and 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 HVAC DTCs and settings will be erased from KAM. The body control module (BCM), which is the vehicle mode master,
provides a device on signal.
The control module supports the features as in the table.
Auxiliary HVAC Control Module
The auxiliary HVAC control module is a class 2 device that receives analog inputs from the front HVAC control assembly and class 2 message inputs
from the rear seat audio (RSA) control module 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.
RSA Control Module
The RSA Control Module is a class 2 device that interfaces between the rear seat passengers and the auxiliary HVAC control module. The battery
positive voltage circuit provides power that the control module uses for keep alive memory (KAM). Air temperature, blower motor and air delivery
rocker type switches are located on the face of the module. These switches enable the module to send a class 2 serial data message to the auxiliary
HVAC control module for the change request. The module does not store auxiliary HVAC DTCs.
Front Auxiliary HVAC Control Assembly
The front auxiliary HVAC control assembly is a non-class 2 device that interfaces between the front seat occupants and the auxiliary HVAC control
module. A 5-volt reference is supplied to the control assembly by the auxiliary HVAC control module. The control assembly varies the 5-volt
reference through three integrated potentiometers to control mode, air temperature door position, and blower motor speed inputs to the auxiliary
HVAC control module.
AIR TEMPERATURE
HVAC Control Module
The HVAC control module is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and 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 HVAC DTCs and settings will be erased from KAM. The body control module (BCM), which is the vehicle mode master,
provides a device on signal.
The control module supports the features as in the table.
