Carlos --

If you find power at the switch but the fan does not work in high speed, then it's likely the motor is burned out.

The slower speeds are created by sending the motor current through a large resistor (next to the blower motor) -- but full speed is full power. If you had lost a slower speed only, then the resistor is generally at fault.

If the bearings were seized, which is not uncommon (and can sometimes be fixed by cleaning and lubing), you would have experienced months or years of squeaking, screeching, chirping, grinding noises before total failure. You would also have noticed the fan running more and more slowly as the bearings dried out.

That's the good news.

The bad news is that Volvo started with the blower motor and built the car around it.