HVAC Programmer

The heater and A/C programmer contains a microprocessor and controls the electronic A/C system. The programmer receives electrical signals from the heater and A/C control, sun load sensors, ambient temperature sensor, inside temperature sensor, blower control module, powertrain control module, mode selector switch, and actuators. A microprocessor in the programmer processes the signals and then sends commands to the system components that control A/C compressor clutch operation, air intake location, air discharge location, air discharge temperature, and blower speed.

The heater and A/C programmer also performs self-diagnosis functions for the electronic A/C system. When the system diagnostic mode is activated through a scan tool, these faults are displayed as a numeric diagnostic trouble code (DTC).