fusible link tawag dyan, normally put on large ampere connections from/to the battery. since '96 pa car mo and di ka pa siguro nagpalit kahit minsan ng fuses mo, then it may just have run out of it's useful life kaya nasunog.

if you can get hold of a clamp ammeter, measure the current running through that line. if the ampere reading is below the fusible link rating then there's nothing to worry about. if it is higher then have an electrician look at it again.

do i need say that the clamp ammeter must be set for reading DC ampere? sana naman hindi na. otherwise you will really have to see an electrician.