Bob,

That seemed to be a transition period for horn relays in the AD trucks. They were located near the driver side hood hinge on the fire wall. A horn relay would make the system better, but one has to wonder why yours is pulling so much current that it is melting things.

Before I retro fitted with the relay, I would test what is there now, and try to find why it is doing this. Could the horn have stuck at some point, and this melting thing was a one shot deal!

Your system must supply ground to a insulated horn. Maybe something inside the horn proper is gunny-bagged..I don't know. Grab your little voltage tester and do some more detective work. Keep us posted!

Stuart