CTS V8-5.7L VIN P (2004)
Air Door Actuator / Motor: Description and Operation
Air Temperature
AIR TEMPERATURE ACTUATORS
The air temperature actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5-volt reference,
position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12-volt value to coordinate the actuator
movement. When the actuator is at rest, both control circuits have a value of 0 volts. In order to move the actuator, the HVAC control module grounds
one of the control circuits while providing the other with 12 volts. The HVAC control module reverses the polarity of the control circuits to move the
actuator in the opposite direction.
When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 volts. The HVAC control module
uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets
a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module.
Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.