The mechanical air conditioning system is not working (LUPO 3L from 2001). A switching condition is a running fan. However, it does not. The fan control unit has been replaced 3 years ago., the Lupo was deregistered 2 years ago. A 30A fuse on the fuse carrier (SA 4) was melted, a new one I used, but neither burns through, nor did it have an effect. In order to exclude the fan as a cause, I gave 14 V directly to the plug via an external power source(d However, it delivers a maximum of 2.5 A at 14 V). In the case of contact 1 (mass) and 3, the fan does not run, in the case of contact 1 and 2. However, since I do not know if this is really a separate circuit the question is: can I check it as I did it, or is it possible to do it differently? My diagnosis so far is that one stage of the fan is defective and therefore I need a new one. These are available in the form oval (most expensive variant 34 €) or form flat (a few euros more). I just take the oval shape? Do you have to solve the coolant hoses in order to expand the fan, because there is very little space there or can you get that even without draining the coolant? Many questions, but I haven’t found anything in the Lupo Forum yet.