Replaced my wiper and directional switches on the column recently. After putting everything back together, my horn now goes off when I turn the steering wheel. I'm assuming I must have messed up a ground somewhere, but I can't find the ground wire for the horn. Is that part of the wire loom in the directional switch.

Depends on the year of your car:

Early ('69 - mid? '72) you have an elongated spring loaded button that goes from the contact ring to the steering wheel center pad.

Late (mid '72 - up) you have a brown wire that comes up from the contact ring (essentially) and hooks to a spade terminal on the steering wheel center pad.

Both are grounds which complete the electrical circuit when the center pad is pushed.

When not pushed, it usually means one is contacting metal due to a frayed wire or improper assembly.

Its a 73. The horn will go off with or without the horn button connected. Is there a ground wire in the wire bundle for the wipers and directionals?

There is a ground wire on the combination switch that runs from terminal 31 on the switch to Ground Connection B, but that's not the one that would activate the horn.

There is a wire (brown/ white trace) that runs from the horn relay to terminal 37 on the combo switch. It is actually the ground for the solenoid in the relay. When the circuit is completed by activating the relay (pushing the center of the steering wheel), power goes to the horns.

I have never located a "horn relay", but the wiring diagram says there is one.

The power wire is black w/ yellow trace that runs from the relay to the horn(s). Power lead to the relay is from fuse #8.