General Description; Auto A/C System Description; Hvac Control System Description - Suzuki Grand Vitara 2011 Manual

7B-5 Air Conditioning System:

AUTO A/C System Description

The automatic air conditioning system (auto A/C), HVAC
control module automatically controls inside air
temperature, blower speed, airflow outlet and so forth.
Once users set up desired inside air temperature with
the temperature control selector, select "AUTO" position
of blower speed selector and push auto A/C switch,
HVAC control module detects inside air temperature,
outside air temperature, amount of sunlight, and engine
coolant temperature by means of inside air temperature
sensor, outside air temperature sensor, sunload sensor,
and engine coolant temperature (ECT) sensor
respectively.
Then, HVAC control module keeps desired in-car
temperature at any time.
Then, HVAC control module keeps in-car temperature at
desired level and auto A/C indicator lamp of HVAC
control module turns on.

General Description

HVAC Control System Description

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For CAN communication system, refer to description on
"CAN Communication System Description: For Petrol
Engine Model in Section 1A".
When following data are sent from control modules to
BCM through CAN communication, they are sent from
BCM to HVAC control module through serial
communication line.
• Engine coolant temperature
• Engine speed
• A/C refrigerant pressure
• Vehicle Speed (wheel speed)
• Outside air temperature
Based on above data, HVAC control module sends A/C
compressor ON / OFF request signal to BCM through
serial communication line.
BCM sends this signal through CAN communication to
ECM which then causes compressor relay to turn ON /
OFF.
For more information on signal transmission and
reception of Auto A/C system, refer to "Auto A/C
Electronic Control Input / Output Diagram".
HVAC control module has a function to make initial
settings of temperature control actuator, air intake
actuator and air flow actuator.
Initial settings of actuators are automatically made when
engine is started for the first time after battery is
connected.
When initial settings are made, each actuator is forced to
operate for about 15 seconds continuously.
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