Peugeot 406 - interior fan on constantly

there are different methods of controlling the fan speed on different models depending on year of manufacture and spec'. give more information - model, year, description of switch, a/c fitted or not, dual zone, chassis no. etc. whatever might be relevant.  there are different methods of controlling the fan speed on different models depending on year of manufacture and spec'. give more information - model, year, description of switch, a/c fitted or not, dual zone, chassis no. etc. whatever might be relevant.