Hello, some time ago I noticed that my Lupo ANV 1.0 50ps got warmer than usual. Actually it always keeps the temperature at 90° Now I’ve been on the highway for quite a long time and it was constantly at about 100-105° when I was stuck in the traffic jam it even went over 110° and the lamp went on. Coolant is still quite fresh and enough there. Water pump is not too old. Heating works. On the highway at little speed and low speeds go Somehow I have the feeling that the fan doesn’t work anymore. When should it turn on? When the temperature was at such 100° I opened the bonnet. The fan was off. How should I proceed to troubleshoot it?