Sorry for the late response.

Best place to start is a wiring diagram. Do you have one? (Not being sarcastic).

If both buttons don't work it sounds more line an issue with where the wire transitions from the steering wheel to the wiring in the steering column (burnt wire, broken wire, wire popped out of connector, pin in connector melted in connector etc). Anything that would stop current from getting to where the switches are.

I will got out on a shaky limb of a small tree and say that it likely happened that the previous owner honked at anything that moved and held the button down for 10 seconds at a time and overheated the wiring or a pin in the connector.
Both can be fixed. It's just a question of dismantling things in a logical order until we find the break in the circuit.

 

Is the airbag light on also? People have been known to disconnect or cut the clock spring to kill the airbag for smaller drivers. This also disconnects the horn on some models.

 

Honk! Honk!

Anyone home?

 

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