Theory Of Operation

The Electric Vehicle Control Unit (EVCU) monitors the A/C Pressure Transducer (Sensor) voltages and broadcast the voltage reading over the Bus. The A/C Pressure Transducer connects to a fitting on the A/C discharge line and its internal resistance changes in relation to the pressure in the system. The EVCU provides a 5-Volt reference signal and a sensor ground to the A/C Pressure Transducer, then monitors the output voltage of the transducer on the sensor signal circuit to determine refrigerant pressure. The EVCU is programmed to respond to this and other sensor inputs and activates the Radiator Cooling Fan to help optimize A/C system performance and to protect the A/C system components from damage.