[argonaut]

Was it the big 10 or 12AWG wire that mounts to the post? If so this is the main power wire coming off the alternator and connecting to the battery and the fuse panel.
If it was disconnected, then your battery has been draining while the truck is running.
If this grounded out then you could have melted some of the wiring that goes down to the horn relay junction mount, and over through the core support to the battery.

So I would check to see if a) your battery is dead and b) if the wiring is okay.