A melting plug can't happen on its own from too much current because ideally, it has no resistance, so there's no voltage drop, and no heat buildup. HOWEVER, undesired resistance WILL cause heat buildup that can melt the plug. That resistance appears at the connection between the terminal in the plug and its mate on the switch, or between the contacts inside the switch. When that happens, both the switch and the offending terminals must be replaced. Typically you'll find two wires in the plug that are hardened for about 4" from being overheated. That 4" of wire must be cut out and replaced, the switch must be replaced, and the overheated terminals must be cut out of the plug and replaced. The entire plug does not have to be replaced. Cut out the melted parts, install crimp-type terminals to the new spliced-in sections of wire, and plug them in individually.
If you don't replace everything at the same time, the high resistance will continue to develop heat and transfer it to the new parts, and the problem will pop up again.
Sunday, August 14th, 2011 AT 10:42 PM