I had a BMW that sat for a while and mice built a nest in the blower. I tore apart the dash, cleaned it out and the next year they did it again, only this time they chewed up the wiring. I had to replace it all after that.

It could just be slightly stuck from sitting and if you can get it to turn it might start working fine again. Don't burn it up trying though. Maybe try shooting some compressed air into the fan to get it turning? I don't know if that's feasible or not, just a thought.