The HVAC Control Assembly receives an actuator position signal from the RH and LH electric actuators. The electric actuator position sensor is a potentiometer that is tied to a 5 volt reference source through CKT 1791 and to ground through CKT 1798, both from the HVAC Control Assembly. The variable output from the potentiometer feeds back a position signal to a pull-up resistor located in the HVAC Control Assembly. This signal is used to determine the necessary drive signal to the electric actuator motor to provide the proper air mix door position. This value is stored in the Keep Alive Memory (KAM) portion of the HVAC Control Assembly.

After replacement of either the LH or RH electric actuator has been completed, reinitialization of the actuators must be performed. Reinitialization can be easily executed by removing the HVAC CON MiniFuse® #27 from the Instrument Panel Electrical Center and then reinstalling the fuse back into its proper position. When the HVAC Control Assembly is first connected to power, the system will perform an initialization routine lasting approximately 60 seconds. During this routine, both RH and LH electric actuators will cycle full travel in both directions learning the end positions. Position feedback readings are sent back to the HVAC Control Assembly and compared to a range of acceptable end readings. If during initialization the position feedback readings are not within the acceptable range, a diagnostic code will be set. If the position feedback readings reach values of 0-5 counts or 250-255 counts, the HVAC Control Assembly will then interpret the reading as a "feedback-short" or "feedback-open" condition respectively. NOTE: Feedback-short or feedback-open conditions can occur due to electric actuators being initialized while not being attached to the HVAC module case.