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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1418 (HVAC Systems - Automatic) >> Description and Operation >> Air Delivery Description and Operation >> HVAC Control Components >> Auxiliary Console Mode Actuator

Auxiliary Console Mode Actuator

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The auxiliary console mode actuator is a 5 wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5 volt reference, position signal, and two control circuits enable the actuator to operate. The control circuits use either a 0 or 12 volt value to co-ordinate 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 auxiliary HVAC control module grounds one of the control circuits while providing the other with 12 volts. The control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometer's adjustable contact changes the door position signal between 0-5 volts.

The auxiliary 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 grounds both control circuits.