Titan 2WD V8-5.6L (VK56DE) Flex Fuel (2009)
When A/C switch or DEF switch is pressed, front air control inputs compressor ON signal to BCM.
BCM sends compressor ON signal to ECM and front air control, via CAN communication line.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant pressure sensor signal, throttle angle sensor, etc.). If it
judges compressor can be turned ON, it sends compressor ON signal to IPDM E/R, via CAN communication line.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate compressor.