[BlueSpark]

I am real curious about this. The horn relay has 3 terminals, right?

One is the coil (-) that connects to the battery negative.
One is the other side of the coil which is grounded when horn button is pushed.
One is one side of the relay contact that connects to the horns.
The other side of the relay contact connects to the battery side of the coil internally to the relay.
So here are the jumper possibilities (I arbitrarily numbered the terminals):
1-2 fuse will blow as soon as horn button is pushed
2-3 fuse will blow as soon as horn button is pushed
1-3 horn will blow continuously regardless of button
So the only configuration that will work is 1-3 with a modification to the car horn button to supply 6V when the horn button is pushed rather than providing ground to the coil. But, the reason for the horn relay is to handle relatively high current which would cook the contacts of the horn button so there would need to be a higher current button or another relay.