The blend door actuator (1) is a reversible, 12 volt
direct current (DC), servo motor. The blend door
actuator is located on the top of the HVAC housing.
The blend door actuator is interchangeable with the
actuators for both mode-air doors and the recircula-
tion-air door. Each actuator is contained within an
identical black molded plastic housing with an integral
wire connector receptacle. Three integral mounting
tabs allow the actuator to be secured to the HVAC
housing. Each actuator also has an identical output
shaft with splines that connects it to the blend-air door.
The blend door actuator does require mechanical
indexing to the blend-air door, as it is electronically
calibrated by the A/C-heater control.

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 both connections low, the blend-air door
stops and will not move. The A/C-heater control uses a pulse-count positioning system 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 circuit.

The blend door actuator cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The blend door actuator is diagnosed using the scan tool. Refer to 24 - HVAC Electrical Diagnostics for more
information.

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CONTROLS - FRONT

REMOVAL

1. Disconnect and isolate the negative battery cable.

2. Remove the instrument panel assembly (Refer to

23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - REMOVAL).

3. Remove the screws (4) that secure the blend door

actuator (2) to the top of the HVAC housing (3).

4. Disconnect the HVAC wire harness connector (1)

from the blend door actuator.

5. Remove the blend door actuator from the HVAC

housing.

INSTALLATION

1. Position the blend door actuator (1) onto the top of

the HVAC housing (2). If necessary, rotate the
actuator slightly to align the splines on the actuator
output shaft (3) with those on the blend-air door
linkage (4).

CONTROLS - FRONT

24 - 335

2. Install the screws (4) that secure the blend door

actuator (2) to the HVAC housing (3). Tighten the
screws to 2 N·m (17 in. lbs.).

3. Connect the HVAC wire harness connector (1) to

the blend door actuator.

4. Install the instrument panel assembly (Refer to 23 -

BODY/INSTRUMENT

PANEL/INSTRUMENT

PANEL ASSEMBLY - INSTALLATION).

5. Reconnect the negative battery cable.

6. Initiate the Actuator Calibration function using a

scan tool. Refer to HVAC System Test, found in 24
- HVAC - Electrical Diagnostics.

ACTUATOR-MODE DOOR

DESCRIPTION

The two mode door actuators (floor/defrost and panel
door) (1) are reversible, 12–volt direct current (DC),
servo motors. Both mode door actuators are located
near the drivers side end of the HVAC housing. The
mode door actuators are mechanically connected to
the floor/defrost and the panel-air door. Both mode
door actuators are interchangeable with each other
and with the actuators for the blend-air door and the
recirculation-air door. Each actuator is contained within
an identical black molded plastic housing with an inte-
gral wire connector receptacle. Three integral mount-
ing tabs allow the actuator to be secured to the top of
the HVAC housing. Each actuator also has an identi-
cal output shaft with splines that connects it to the
mode-air doors. The mode door actuators do not
require mechanical indexing to the mode-air doors, as
they are electronically calibrated by the A/C-heater
control.

OPERATION

The floor/defrost and panel (mode) door actuators are connected to the A/C-heater control through the vehicle elec-
trical system by a dedicated two-wire lead and connector of the HVAC wire harness. The mode door actuators can
move the floor/defrost and the panel-air doors 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 mode-air door(s) will move in one direction.
When the A/C-heater control reverses the polarity of the voltage to the motor, the mode-air door(s) moves in the
opposite direction.

When the A/C-heater control makes the voltage to both connections high or both connections low, the mode-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 floor/defrost and panel door actuators and the mode-air doors. The A/C-heater
control learns the mode-air door stop positions during the calibration procedure and will store a diagnostic trouble
code (DTC) for any problems it detects in the mode door actuator circuits.

The mode door actuators cannot be adjusted or repaired and, if faulty or damaged, they must be replaced.

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CONTROLS - FRONT

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