The AC indicator light of Geely Emgrand ec7-RV air conditioner is not on, and the air conditioner does not cool.

The owner reported that the air conditioner did not cool. After inspection, it was found that there was enough refrigerant. When the vehicle was started and the AC button of the air conditioner was pressed, it was found that the light was not on, and everything else was normal. First, use the decoder to enter the air conditioning system for fault reading, and found that there was no fault code. Then read the data stream and found that the external ambient temperature sensor showed -30°. Obviously, the data stream is abnormal. The sensor was found at the front bumper and unplugged. It was found that the interior was corroded due to water ingress. The line was measured to be a ground wire and a 5v power supply. Both were normal. After cleaning, the data flow was still -30° when the plug was plugged in, so the vehicle was powered off for one minute. After connecting the power supply, the data flow was read again. At this time, it was 29°. The AC indicator light of the vehicle turned on and the air conditioner was lit normally, and the compressor also worked accordingly. At this time, the fault was solved!