Had headlights, then high beam only, now nothing

Okay, had a lot of other things going on, on top of me trying to understand what happened to the Swinger, with the headlights & such. I don't remember if I mentioned it or not, but several times, last year, I had some head light issues on the '08 Town & Country, that were driving me up the wall, because the electrical system on them, is a whole different matter. Doesn't help, that even though I have maintained our vehicles, since way back & hadn't until a few years back (I'm 72 now), had issues like this & had NEVER had light issue, on a vehicle of any kind, with basically the old school electrical system in it. So, I have now, started really digging into the electrical system in this one.I started off, by eliminating the crudely installed aftermarket stereo (not only eliminating the radio & it's mess of wiring, it opened things up some, under the dash, to help me be able to better check things out, under there. Under the hood, I had removed the main connectors, on the firewall & checked the condition of the connectors there & felt they were okay, though I went ahead & did some scrapping on them, in an attempt to make sure of the connections., but somehow I missed the fact that there is a red fusible link that is inline, from the battery, to the Amp meter. Now while it is still in place & apparently making a connection (since the meter works) I have to wonder if I should replace it, as the insulation indicates, it has been pretty warm, as it has split and doesn't really cover the wire & I know it is a hazard, to be in that condition & could end up causing a short. My main question is though, can you even get fusible links any more? I am thinking it would be better, to remove it & replace it with a fuse holder with wire on both ends & connectors. I am just not sure what amperage the fuse should be? I will continued with working on my original issue, of course, but I want to take care of this first. Any input appreciated.