Viper SRT-10 V10-8.4L (2008)
Air Door Actuator / Motor: Description and Operation
Blend Door Actuator
Description
DESCRIPTION
The blend door actuator is a reversible, 12-volt, direct current (DC) servo motor which mechanically positions the blend-air door.
The blend door actuator consists of a black molded plastic housing (1) with an integral wire connector receptacle (2) and three integral mounting tabs (4)
that allow the actuator to be secured to the HVAC housing. The blend door actuator also has an output shaft with splines (3) that connect it to the linkage
that drives the blend-air door.
The blend door actuator is located on the top of the HVAC housing and does not require mechanical indexing to the blend door linkage, as it is
electronically calibrated by the A/C-heater control.
Operation
OPERATION
The blend door actuator is connected to the A/C-heater control through the vehicle electrical system by a dedicated two-wire lead and connector of the
HVAC wire harness. The blend door actuator can move the blend-air door in two directions. When the A/C-heater control pulls the voltage on one side
of the motor connection high and the other connection low, the blend-air door will move in one direction. When the A/C-heater control reverses the
polarity of the voltage to the motor, the blend-air door moves in the opposite direction. When the A/C-heater control makes the voltage to both
connections high or low, the blend-air door stops and does not move. The motor connections also provide a feedback signal to the A/C-heater control.
This feedback signal allows the A/C-heater control to monitor the operation and relative position of the blend door actuator and the blend-air door. The
A/C-heater control learns the blend-air door stop positions during the calibration procedure and will store a diagnostic trouble code (DTC) for any
problems it detects in the blend door actuator circuits.
NOTE: If battery voltage is low or not sensed at the blend door actuator for less than a 60 second interval, the blend door actuator will be out
of calibration. Remove fuse #3 BCM1 (I.O.D. fuse) for a minimum of 60 seconds. The blend door actuator will then self calibrate upon
reinstallation of the fuse.
The blend door actuator is diagnosed using a scan tool See: Testing and Inspection/Symptom Related Diagnostic Procedures/HVAC System Test.
The blend door actuator cannot be adjusted or repaired and must be replaced if inoperative or damaged.
