1969 gmc 1500 custom 4x4
 

having trouble with a short to ground smoked a wire from the pos side of the battery that goes to a ter;minal and to a wire bundle that goes to the firewall. the only thing i did was change battery and it started to happen. could it be the ignition switch? it looks like this wire goes to the ignition switch after it comes out of the firewall. i changed the battery cables neg and pos. and change the wire that smoked with an inline fuse.

help