This clock spring was bad. My horn only worked when the steering wheel was turned to the left.
So I replaced it.
Notice that the mark on the nut doesn't line up. Several online posts and YouTube pros say that the torque on that nut is 37 ft lbs, so that's what I went with. However, it felt like it was on there much tighter than that when I removed it. I had to use a harmonic balancer puller (en lieu of a steering wheel puller) to get the steering wheel off, so I don't think there is too much pressure applied to that nut anyway. Just interesting the difference.
Tested the horn and radio controls. Also tested that I could engage cruise control, but haven't actually tested the CC itself. I imagine if the button registers that it has been pressed, the other buttons will work as well.
In fact, pressing the air bag back in pretty much requires you to press the horn. Until I figured out that I had to pull the little plastic tabs out from the side and get one side in at a time, I tested the horn multiple times. I'm sure the neighbors thought I was durnk.