Blew both front harness fuses - what'd cause that?

[davepl]

My temp gauge doesn't work, and while reading up about it in the forums, I came across a couple of posts that mentioned fuses in the black wires of the front harness, apparently for the ammeter.

I had noticed my ammeter didn't not register anything when I turned the headlights on (not running yet so cannot check charge side).

Both fuses are indeed caked.

So before I just put new fuses in and hope for the best, where would I look first? I've pulled the instrument cluster, so I can easily check stuff on it.

I just don't know what I'm looking for yet...