Check for power and continuity of ground at the horn when the horn button is pressed. Easy to test with a multimeter, but will need a friend to press the horn button.
Check the horn itself by jumpering power and ground from the battery or from a power supply.
If the horn doesn't function after testing, and you have power and ground where you should, replace the horn. They're not usually high quality parts, and they fail.
If you don't power or ground, you'll have to trace back until you find it. If may be a bad fuse, or a corroded ground. I can't see much else happening with a 2015 from a reliability standpoint, so I'll reserve any confusing comments until after you do the easy initial health tests. Basically, I would doubt that your clockspring has failed, but it's very possible a fuse is blown, so always check the easy stuff first.