Mercedes-Benz E-class air conditioner can't cool. What's the problem? What happened?

Check the evaporator temperature. There is a temperature sensor on the evaporator. If the temperature detected by the sensor is lower than 3 degrees, the automobile ECU will also disconnect the compressor relay and stop the compressor from working.

Throttle opening. For example, if the throttle valve fails, the compressor will not work if the opening of 100/ 100 is too large.

Check the air conditioning signal. To turn on the air conditioner, there must be a request signal. First, turn on the blower switch and press the air conditioner switch. These request signals will be sent to the ECU module, and then the compressor will work. If these signals are not received, the compressor will not work.

Check the ambient temperature. There is a sensor on the automobile sensor to detect the ambient temperature. If the ambient temperature is lower than 1 degree, the ECU will not start the compressor after receiving the signal. Some cars don't have a separate ambient temperature sensor, so they use an air temperature sensor instead.