The A/C-heater control panel is a completely electronic control unit. Heater, Ventilation and Air Conditioning (HVAC) control module in integral with A/C-heater control panel. HVAC control module can communicate with other modules through PCI Bus communication network, and can be addressed using DRBIII or compatible generic scan tool. HVAC control module monitors ambient air temperature, evaporator temperature and electronic actuators that control air temperature and route airflow through front and rear HVAC housing (if equipped) to selected outlet vents.
To maintain accuracy, HVAC control module periodically performs a self-calibration test of actuator doors. HVAC control module records actuator revolutions required for full travel of each actuator door motor. Each actuator door can then be positioned by sending voltage pulse signals (in either polarity) to position actuator doors for maximum performance. This simplified method provides positive door positioning, without the complexity of vacuum actuators and feedback from position sensors. A/C system performance is checked using DRBIII or compatible generic scan tool and performing A/C cool down test. A/C cool down test will check the ability of the A/C refrigerant system to reduce evaporator core temperature -20 F (-29 C) within 2 minutes. If calibration or A/C cool down test fail, a DTC/fault message will be stored, and HVAC system performance will be lost. A/C-heater control panel (HVAC control module) is not serviceable, and if found faulty must be replaced as an assembly.
Sunday, January 2nd, 2011 AT 2:37 PM