I had similar circumstances. Replaced the resistor pack once, then a while later (year or couple years) the blower actually went out. It only ran sporadically, then only on high, and later it cut off all together. I opened up the compartment on the firewall from inside the engine compartment, and turned the blower motor blower wheel, and dang it started to work. I ended up buying a new blower to fix it. Turned out the brushes on the old motor were completely worn. Prolly could have simply fixed it with new brushes, but I just replaced the whole darn thing.