[RandyP]

Originally Posted by gchemist

You fried the fusable links. Wires light up like that when they are crossed or system has a reverse feed somewhere. Dead battery ground should be hooked up last!! Ground on dead battery should be avoided. You should hook it directly to a metal bracket or engine bracket. I like using the alternator bracket.

Oh, cheap jump wires light up like that too.

Exactly. Always do positive and then ground, and ground away from battery. I was always taught that to avoid the spark, which could ignite if the battery has a fume buildup around it. Of course with most sealed batteries these days, probably not as big of an issue. I'm guessing probably bad jumper cables were the root of the evil here.