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Chrysler 300/300 Touring/300C, Dodge Magnum. Manual - part 2326
ACTUATOR-BLEND DOOR
DESCRIPTION
The blend door actuators (1) are reversible, 12 volt
direct current (DC), servo motors. Models equipped
with the MTC single zone heating-A/C system have a
single blend-air door, which is controlled by a single
blend door actuator. Models with the ATC dual zone
heating-A/C system have two blend-air doors, which
are controlled by two blend door actuators.
The blend door actuator for the single zone heating-
A/C system is located on the driver side end of the
HVAC air distribution housing, close to the dash panel.
For the dual zone heating-A/C system, the same
blend door actuator used for the single zone system
becomes the driver side blend door actuator, which is
mechanically connected to only the driver side blend-
air door. A second separate blend door actuator is
also located on the passenger side of the HVAC air
distribution housing which is mechanically connected
to only the passenger side blend-air door.
The blend door actuators are interchangeable with
each other, as well as with the actuators for the mode-
air door and the recirculation-air door. Each actuator is
contained within an identical black molded plastic
housing with an integral wire connector receptacle (2). Each actuator also has an identical output shaft with splines
(3) that connect it to its respective door linkage and three integral mounting tabs (4) that allow the actuator to be
secured to the HVAC housing. The blend door actuators do not require mechanical indexing to the blend-air doors,
as they are electronically calibrated by the A/C-heater control.
OPERATION
The blend door actuators are connected to the A/C-heater control through the vehicle electrical system by a dedi-
cated 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(s) stops and will not move. The A/C-heater control uses a pulse-count positioning system to monitor the oper-
ation and relative position of the blend door actuators and the blend-air doors. The A/C-heater control learns the
blend-air doors 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.
(Refer to 24 - HEATING & AIR CONDITIONING - DIAGNOSIS AND TESTING - HEATING AND A/C SYSTEMS) and
to 24 - HVAC Electrical Diagnostics for more information.
The blend door actuator(s) cannot be adjusted or repaired and, if faulty or damaged, they must be replaced.
REMOVAL
WARNING: On vehicles equipped with airbags, disable the airbag system before attempting any steering
wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the
negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before
performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to
take the proper precautions could result in accidental airbag deployment and possible personal injury or
death.
24 - 338
CONTROLS
LX