Thank you very much.
Well, the strange thing is that until now the fan worked on low speed. Only a few days ago it stopped working at all. I think the resistor connector is a little bit melted (it has some black areas in it). Maybe that's why it stopped working. Long time the fan was working only on high speed. Sometimes this can melt connectors, right? I will try to find another one and change it but I will also check the fuses too.
I don't think is very expensive to find a resistor too, and in this way I will find out if this was the problem. But as I understand from what you just said... there cannot be another problem.
[LE]: Oh, and sorry. I've never used the a/c because it's not working. So all these happened with a/c off.
The fans can be spun freely by hand. They look ok.