No sound from horn

I went for a ride with my son last night and noticed no sound was coming from my horn. I assumed the horn failed so this morning I replaced the XT225 horn with a known working nicer horn from one of my ATV’s. Still no sound with the replacement horn. I opened up the handlebar switch where the horn button is and the connections looked solid, not even a spec of dust inside there. At that point the issue wasn’t obvious and it was about 108 degrees outside so I put my tools back and walked away. Now I am I trying to troubleshoot from the comfort of my air conditioned house. Does the XT225 have a fuse for the horn? If yes, where is the horn fuse located? Any other ideas on what I should check?

I don't think there's fuse in the horn circuit. Check continuity across the switch to see if the button is working. Check continuity of the wires between the button and the horn to see if you've got a bad wire.

Other than the main fuse, there is no fuse on the horn circuit. The DC that feeds the horn also feeds the turn signal indicator and all the turn signal lamps. Wire color is brown (+12) that feeds the horn. Return to ground from horn (through handlebar switch) is pink. From the switch to frame ground is black to complete the entire circuit.

I've had trouble with the handlebar switches both horn and starter. Your best bet is a VOM or test lamp to check for +12 down the circuit. One side of the horn should be "hot" when the bike is turned on (horn unplugged). I usually use a safety pin to check wires ahead of connections. If the horn and connections are good, the other side should be "hot" too when the horn is plugged in.

If you get these readings, shut the bike off and work from frame ground back up the circuit. Now using resistance or continuity, you should see a "closed" connection on black. Look for an open connection on pink until you press the horn switch. Sometimes a wire can break inside the insulation near a crimp connected terminal. The horn circuit has its own ground (black). Make sure it's good. You can go across pink and black to check just the handlebar switch. Or pink to frame ground to check the black ground wire and switch. That switch is normally open showing continuity when depressed.

Buzzing out these problems is just a systematic checking of each component, all related circuit wires, power and connections. The connections to the horn and the horn itself are exposed. I'd look there first.

The horns on both our bikes have failed. Dirt and water get in there and jams the diaphragm. Hope this helps and good luck!