Control Module HVAC: Description and Operation

AIR DELIVERY

HVAC CONTROL MODULE
The HVAC control module (IPM) is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The dash integration module (DIM), which is the vehicle power mode master, provides a device on signal. The control module (IPM) supports the following features:




The HVAC control module (IPM) will receive information that defines the current driver of the vehicle from the driver door module (DDM) through class 2 communication. The HVAC system will memorize the following system configurations for up to two unique drivers:
- Driver set temperature
- Passenger set temperature
- Mode
- Blower motor speed
- A/C compressor request, auto ON or A/C OFF

This information shall be stored inside the HVAC control module (IPM) memory. When a different driver identification button is selected the HVAC control module will recall the appropriate driver settings. When the HVAC control module (IPM) is first turned on, the last stored settings for the current driver will be activated except for the rear defrost and heated seat settings.

BLOWER MOTOR CONTROL PROCESSOR
The blower motor control processor is an interface between the HVAC control module(IPM) 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(IPM) provides a 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 as a low side control to adjust the blower motor speed.

AIR TEMPERATURE

HVAC CONTROL MODULE




The HVAC control module (IPM) is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The dash integration module (DIM), which is the vehicle power mode master, provides a device on signal. The control module (IPM) supports the following features.