B3779 CHEVROLET – Air Flow Control

B3779 CHEVROLET Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

B3779 CHEVROLET Possible Causes

Faulty Mode Actuator,Mode Actuator harness is open or shorted,Mode Actuator circuit poor electrical connection

B3779 CHEVROLET Description

The Heating, Ventilation, and Air Conditioning (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.