Pc is burning but the fan is in holidays

The title could be quite funny but this is the situation…
The temperature is going from 71°C to 85°C and the fan is always at it’s minimum…
How i can increase the speed of the fan?

DietPi themselves did not have any fan control software. I guess depending on your computer and fan, you would need some additional software like fancontrol

https://unix.stackexchange.com/questions/590307/how-to-manually-set-cpu-fan-speed-in-debian-linux