2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 305
Circuit/System Description
The HVAC control module controls the HVAC door actuators to regulate the airflow through the HVAC system. Each actuator consists of an
electric motor and a potentiometer. The module supplies a low reference and 5-volt reference source voltage to the potentiometer. The HVAC
control module monitors the voltage drop across the potentiometer on the door position signal circuit. When the actuator shaft rotates, the voltage
on the door position signal circuit changes. The control circuit uses either a 0, 2.5 or 5-volt signal to command the actuator movement. When the
actuator is at rest, the control circuit value is 2.5 volts. A 0 or 5-volt control signal commands the actuator movement in opposite directions.
* B0228 is for the recirculate actuator.
* B0413 is for the drivers air temperature actuator.
* B0423 is for the passenger air temperature actuator.
* B0433 is for the auxiliary air temperature actuator.
* B3779 is for the mode actuator.
* B3782 is for the auxiliary mode actuator.
Conditions for Running the DTC
* Ignition ON.
* The HVAC module is ON.
Conditions for Setting the DTC
The actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position
signal circuit is less than 3 counts or greater than 253 counts.
Action Taken When the DTC Sets
The control circuit is deactivated for the appropriate actuator.
Conditions for Clearing the DTC
* The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
* The history DTC will clear after 100 fault-free ignition cycles.
Reference Information
Schematic Reference
HVAC Schematics (See: Heating and Air Conditioning/Diagrams/Electrical Diagrams/HVAC - Manual)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
* Air Delivery Description and Operation (See: Heating and Air Conditioning/Description and Operation/HVAC - Automatic/Air Delivery
Description and Operation)
* Air Temperature Description and Operation (See: Heating and Air Conditioning/Description and Operation/HVAC - Automatic/Air
Temperature Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
