It sounds like you posted a picture, but I don't see any trace of it. In my old Nissan, when they wired in the 7-pin connector, they added an in-line fuse that, as I said was only rated for 20 Amps. When I called about it, I was told it was supposed to be 30.
At any rate, I'm not a bit familiar with the kind of fuse you're describing. I can't believe though, that they'd use a fusible link for that purpose. And, you can SEE that it's blown?
Is there any obvious way to pull the whole box? At least that way you wouldn't be mucking around with live electrical circuits. Failing that, I'd disconnect the NEGATIVE battery cable before you start trying to persuade the fuse out.
- Jack