B0433 HUMMER – Temperature Control #3 Feedback Circuit Malfunction

B0433 HUMMER Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

B0433 HUMMER Possible Causes

Faulty Auxiliary Air Temperature Actuator,Auxiliary Air Temperature Actuator harness is open or shorted,Auxiliary Air Temperature Actuator circuit poor electrical connection,Faulty Auxiliary Heating and Cooling Systems (HVAC) Control Module

B0433 HUMMER Description

The actuators operate using 5 circuits. A 5-volt reference, low reference, signal circuit and two bi-directional 0 or 12 volt control circuits. The Heating, Ventilation, and Air Conditioning (HVAC) Control Module supplies a low reference and 5-volt reference to the potentiometer. The HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. As the actuator door changes position the door position signal circuit voltage also changes. The two bi-directional control circuits enable the actuator to operate. Both circuits are set to 0 volts when the HVAC control module detects, from the feedback potentiometer, that the actuator is in the desired position. In order to move the actuator, the HVAC control module switches the appropriate control circuit to 12 volts.