Dodge ZB 2005 Service Manual page 1048

ZB
BLEND DOOR ACTUATOR
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
is located on the top of the HVAC housing.
The blend door actuator is contained within a
black molded plastic housing with an integral wire
connector receptacle and three integral mounting
tabs that allow the actuator to be secured with three
screws to the HVAC housing. The blend door actuator
also has an output shaft with splines that connects it
to the linkage that drives the blend-air door. The
blend door actuator does require mechanical indexing
to the blend door linkage, as it is electronically cali-
brated 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 take out 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 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 opera-
tion 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 calibra-
tion procedure and will store a diagnostic trouble
code (DTC) for any problems it detects in the blend
door actuator circuit.
NOTE: If battery voltage is low or not sensed at the
blend door actuator for less than a 60 second inter-
val, the blend door actuator will be out of calibra-
tion. 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 can be diagnosed using a
DRBIII scan tool. Refer to Body Diagnostic Proce-
dures for more information.
The blend door actuator cannot be adjusted or
repaired and, if faulty or damaged, it must be
replaced.
REMOVAL
WARNING: On vehicles equipped with airbags, dis-
able the airbag system before attempting any steer-
ing wheel, steering column, or instrument panel
component diagnosis or service. Disconnect and
isolate the battery negative (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 air-
bag system. Failure to take the proper precautions
could result in accidental airbag deployment and
possible personal injury or death.
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the instrument panel (Refer to 23 -
BODY/INSTRUMENT
PANEL ASSEMBLY - REMOVAL).
(3) Disconnect the wire harness connector from the
blend door actuator (Fig. 15).
(4) Remove the three screws that secure the blend
door actuator to the HVAC housing and remove the
actuator.
CONTROLS 24 - 19
PANEL/INSTRUMENT