Halli Hello, is one of you by chance familiar with the Eberspächer D4L year of construction approx. 1990? Just stand in the cold North Macedonia and unfortunately strike my heater for a few days :x. I could identify the following problem: For the first time the error occurred after approx. 15 minutes running time: The fan suddenly only supplied cold air and the heater switched off completely after a while. At the turn on again I noticed that the dosing pump did not tick anymore so I first thought that the pump was running again. However, the pump had to run over the heater and the control unit. That’s why I searched for cable breakage or similar between the pump and the heater installed in a box under the bus and finally arrived at a 5A fuse (this is in the box under the car with the heater), which gave up the spirit. Eventu ell a fuse for overheating?? In any case I changed it because I thought that the fuse might have been material fatigue. After that the heater ran again, where I had never run you for more than 10 minutes. Today again the same problem and again the 5A fuse which has gone away. This time after a run of about a quarter of an hour. So I have the feeling that the fuse gives up every time the heating gets really hot… Does anyone know if the fuse installed in the box below is actually a “overheating protection?”? Bzw. even more important, does anyone know which problem the saying goodbye to the fuse indicates? I would definitely be super grateful if someone could help me, since unfortunately I don’t really know the heating well. Many greetings from the snowy North Macedonia Simon