The evaporator temp sensor is mounted on the evaporator case. Two wires each with a spade connector, don't have the wiring diagram in front of me to look up the color codes. It is a square box, each side about 1", wrapped in felt. A long probe comes off the sensor, and into the evaporator fins. This senses evaporator temperature, and prevents ice up. If the sensor detects icing, no power is fed to the klima, compressor, etc. etc.