Originally Posted by truckernix
I don't know how the horn contact ever was used to carry the full current of the horn. My 51 has the relay on the firewall and the relay supply comes directly from the starter feed. I would suggest buying the relay and installing it. If you haven't tested your horn separately, a stuck contact inside the horn will burn out the horn and maybe the supply circuit too.

I agree, I don't know how that little spring can carry the load. Apparently it can't! I think the correct fix is to add the relay, like you said.

Thanks,
Dave