Heater Fan blowing fuse. Whats the best guess?

Hi all

I have a 93 525iT with an IHRK III if I am not mistaken. The heater fan is working in all speeds but when you are in any speed but 4, there is a distinct electrical burning smell. If I leave the fan in 2 or 3, the fan will cut out and stop from time to time. When the fan is in 4, there is no smell but occaisionaly it will blow the fuse (30 amp fuse makes a mess when it blows)

I realize I have a problem but does this sound like a blower motor failing or a resistor pack on the fritz? I replaced the resistor pack two years ago but who knows, the stealer part may be going south already.

Any thoughts?

Thanks for your time. :D