Hello members, I have been having the following problem with the Smart for 2 weeks. – The engine control light is constantly running – The coolant temperature indicator rises to 120 degrees after approx. 3-5km driving at the current temperatures. – At the same time, the heating is without function. As soon as the temperature rises to 120 degrees, the signal flashes and the Smart runs worse. Shortly afterwards the display drops to 60 degrees and the heating starts to work. From this moment the temperature rises to 90 and stays According to a friend who owns a workshop, the following sensor is defective. “Refrigerant temperature sensor” In addition, I have an appointment with Mercedes on Wednesday to read out the error range. Do these symptoms (motor control light + funny heating or cooling behaviour) have to do with it? What could the problem be? Facts about the car Kilometer: 115tkm Motor: petrol with 40 kW daily driving distance: 25 km (motorway) Greeting