I am about to begin restoring an 86 D350 Single Wheel / 360 Gas truck that my dad owned when I was a kid...looking forward to keeping it going.

My first challenge is the horn randomly blasts away while it is parked. At first I thought there was an issue in the steering wheel pad - but my latest discovery has been whacking the drivers side fender with my fist - and it will stop. Yes I can trace down the wiring - no worries there. My question was more hoping for a "common cause" if anyone has heard of one on these trucks... so I could start there first?

Any takers? I'll be back later for the fun stuff like getting some more horses out of this smogged down 360V8.

 

Is the horn controlled by a relay? If so, replace it. See what happens.

 

whacking the drivers side fender should have no effect on it at all. the relay is on the fuse panel under the dash. it is the square 3 terminal thing. with age it is common for them to either stick open(not work at all) or stick closed when you hit the button(horn continues after you let go of the button). you can try pulling the relay and seeing if it keeps doing it or not. it is possible someone in the past has had the steering wheel off and didn't put things back together right or over tightened the steering wheel. i know mine in my 81 occasionally goes off while steering so i just clipped the wire at the steering column. should be the green one on the outside of larger group of wires.