Sounds like the fan unit itself has seized....
Remove the three bolts from the passenger foot well and drop the fan and try to turn by hand.
You may find it is difficult to turn, a bit of WD40 may help temporary... but a new fan would be best.
Also it still could be the resistors if its a hairline crack in the solder etc... I'd run a multi meter accross it to ensure they are 100% entact and at the correct resistence...
Or... have you checked the fuse?
