smoke in the dash

[allen]

Just got my second T a 26 coupe runs OK, while driving it for the first time notice smoke coming for the switch turn car around and headed home switch from bat to mag and the wire started to cool down. when I got back to the house took the dash out and the red wire (mag) wire was hot and looks like it melted at the switch, never did the amp gage go to a short instead held charge 10 to 12 amps charging. any ideas thanks AL