HVAC Control System Description (For Vehicle Without A/C)

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. For CAN communication system, refer to description on CAN COMMUNICATION SYSTEM DESCRIPTION .

• Engine coolant temperature
• Engine Speed
• Wheel speed (Vehicle speed)

HVAC control module has a function to make initial settings of temperature control actuator, air intake actuator and air flow actuator.

For vehicle without A/C, HVAC control module uses engine speed signal so that temperature control actuator, air intake actuator and air flow actuator can make initial setting for door position.

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.