You are right, horn CAN NOT normally be operated without horn button being pushed. But you don't have a horn button installed. So if all is wired properly and you said:
"On the horn relay, the brown wire on the right goes to the steering column."
Are we supposed to know what that means? Is the wire bare end, or a frayed part touching metal? What is that wire doing? Where exactly is it?
As I already explained, the horn wire is grounded by the button. Grounded means touching column metal. That's how it completes the circuit and trips the relay. So if "column wire" is touching metal, it's trying to honk the horn............or the relay is bad or the horn itself is wired wrong.
You are having trouble being exact. Pretend we are not there to see what you see, because we are not.
