Thanks to this thread I got my blower motor working again. I too found a hairline crack across the middle, just as I did for the rollbar fuse a few years ago. What I find curious is that these weren't blown (or melted) from shorts. They seem to be mechanical breaks. I'm no stranger to metal fractures, so I'm guessing it's from thermal fatigue. They are made of zinc and are held fast at each end. These strip fuses merit a redesign. Probably something with a bend in it, like most modern automotive fuses.