Gah! On my 97 Rodeo (Passport), the battery failed about 1.5 months ago. I replaced both the alternator and the battery. Tonight I had smoke coming from my hood; I opened it up and saw both my +/- leads smoking at the battery. Closer inspection revealed that wire coverings melted down about 7 inches away from the battery, and the battery covering/plastic is melted around the terminals as well.

What could this be? Alternator overcharging the battery? Faulty battery?