This sensor is a component of the automatic air conditioner, and corresponds to the indoor air outlet temperature sensor. Their temperature signals are used by the control module to determine the temperature difference and the length of the air conditioner. The main function of the temperature sensor outside the vehicle is to provide the ECU with a temperature signal outside the vehicle compartment. Based on this signal, the ECU compares the temperature signal inside the vehicle to determine the temperature inside the vehicle compartment to meet the needs of the personnel inside the vehicle compartment. For example: outside the car is 5 degrees, inside the car is 30 degrees, the temperature difference is too large, the ECU must control the air conditioning work, so that the temperature in the car is reduced to about 20 degrees, at this time people will not feel too hot in the car, also It won't be too cold.