Horn switch

[Eskimomann209]

The horn is ground control through a relay. If it were me I would take the signal wire to the relay and split it using an old fashioned floor mounted dimmer switch. The wire that would normally be power coming into the dimmer switch would be the wire from your horn button. The wire to the low beam side would be one relay for your standard horn. The high beam side with then become your Dixie horns via another relay.

Id use a push button on the floor for the whole thing
Just press down with your foot to make the Dixie horn go

 

[Eskimomann209]

Kinda a pain to hold down the horn on the wheel while trying to make a turn

Works great for the quick "F " you style horns
Train horn or tug boat horn
But if you want a long chime while turning the corner to your friends place

Floor switch all day

 

[BoxerPitMix]

Should be pretty easy.

I'm not sure if the horn contacts in the steering wheel connects a ground or a 12v+ though, so let me see what I can find there. I would think it's 12v+, so in that case and assuming your Dixie horn also uses 12v+ as it's trigger, you'd just disconnect that wire(or cut it if you don't mind cutting stuff), run it to the middle position on a A/B toggle switch and run one of the other poles on the switch(we'll call that "A") out to the stock relay(the wire you disconnected or cut) and the other pole(we'll call that "B") would go to your Dixie horn.

When the A/B switch is in the A position, everything is normal, when it is in B position your Dixie horn will be triggered by your steering wheel.

It's a ground wire, Brown on the ignition harness if I remember correctly.
Unless I was already under there installing an alarm or something, I hate taking that part of the dash apart beneath the column. Much easier to just catch it as a 12v+ in the engine bay if you're connecting it to the factory horn switch anyway.

The horn is ground control through a relay. If it were me I would take the signal wire to the relay and split it using an old fashioned floor mounted dimmer switch. The wire that would normally be power coming into the dimmer switch would be the wire from your horn button. The wire to the low beam side would be one relay for your standard horn. The high beam side with then become your Dixie horns via another relay.

This.
You could even run it beneath the carpet if you wanted to hide it.