The blend door actuators are 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(s) can move the blend-air door(s) 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 both connections low, the blend-air door stops and will not move.
The A/C-heater control uses a feedback signal positioning system to monitor the operation and relative position of the blend door actuator(s) and the blend-air door(s). 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.
The blend door actuators are diagnosed using a DRBIII Â scan tool. Refer to the appropriate diagnostic information.
The blend door actuators cannot be adjusted or repaired and, if faulty or damaged, they must be replaced.
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Saturday, July 18th, 2009 AT 11:26 PM