Suzuki XL7 2007 Service Manual page 1816

7A-2 Heating, Ventilation and Air Conditioning:
headliner outlets. Floor air is directed through floor
outlets, the location of the floor outlets is directly behind
the second row seats.
Mode Actuator
The mode actuator is a 5-wire bi-directional electric
motor that incorporates a feedback potentiometer. Low
reference, 5-volt reference, position signal, and 2 control
circuits enable the actuator to operate. The control circuit
uses either a 0 or 12-volt value to coordinate the
actuator movement. When the actuator is at rest, both
control circuits have a value of 0 volts. In order to move
the actuator, the HVAC control module grounds one of
the control circuits while providing the other with 12 volts.
The HVAC control module reverses the polarity of the
control circuits to move the actuator in the opposite
direction. When the actuator shaft rotates, the
potentiometer's adjustable contact changes the door
position signal between 0-5 volts.
Auxiliary Mode Actuator
The auxiliary mode actuator is a 5 wire bi-directional
electric motor that incorporates a feedback
potentiometer. Low reference, 5 volt reference, position
signal, and two control circuits enable the actuator to
operate. The control circuits use either a 0 or 12 volt
value to coordinate the actuator movement. When the
actuator is at rest, both control circuits have a value of 0
volts. In order to move the actuator, the auxiliary HVAC
control module grounds one of the control circuits while
providing the other with 12 volts. The control module
reverses the polarity of the control circuits to move the
actuator in the opposite direction. When the actuator
shaft rotates, the potentiometer's adjustable contact
changes the door position signal between 0-5 volts.
The auxiliary HVAC control module uses a range of 0-
255 counts to index the actuator position. The door
position signal voltage is converted to a 0-255 count
range. When the module sets a commanded, or
targeted, value, one of the control circuits is grounded.
As the actuator shaft rotates the changing position signal
is sent to the module. Once the position signal and the
commanded value are the same, the module grounds
both control circuits.
Blower Motor Control Processor
The blower motor control processor is an interface
between the HVAC control module and the blower motor.
The blower motor speed control, battery positive voltage
and ground circuits enable the control processor to
operate. The HVAC control module provides a pulse
width modulation (PWM) signal to the control processor
in order to command the blower motor speed. The
processor supplies 12 volts to the blower motor through
the blower motor voltage supply circuit. The control
processor uses the blower motor ground or low
reference as a low side control to adjust the blower
motor speed.
Air Speed
The blower motor forces air to circulate within the
vehicles interior. The vehicle operator determines the
blower motors speed by placing the blower motor switch
in a desired speed position. The blower motor will only
operate if the blower motor switch is in any position other
than OFF, and the ignition switch is in the RUN position.
Once a blower speed is selected, the blower speed
remains constant until a new speed is selected.
As the requested blower speed increases, the following
conditions occur:
• The HVAC control module increases the amount of
time that the blower motor speed control circuit is
modulated to ground.
• The voltage and duty cycle, measured between the
blower motor speed control circuit and ground,
decrease.
As the requested blower speed decreases, the following
conditions occur:
• The HVAC control module decreases the amount of
time that the blower motor speed control circuit is
modulated to ground.
• The voltage and duty cycle, measured between the
blower motor speed control circuit and ground,
increase.
Afterblow
Afterblow is a feature that dries the evaporator core by
operating the blower motor after the engine is turned off.
This reduces the microbial growth that can create
undesireable odors. The vehicle does not come with the
afterblow feature enabled. If the afterblow feature is
required due to an odor concern, it must be turned on by
the scan tool. Certain items need to have happened for
afterblow to operate:
• The A/C compressor operated on the latest key cycle.
• The system voltage is at least 11 volts to start and 10
volts to continue to run.
• The ignition has been in the OFF position for at least
30 minutes.
Once the above conditions have been met the following
sequence of events will occur:
• The blower will run for roughly 2 minutes.
• The recirculation door moves to the outside air
position.
• The mode valve moves to the floor position.