Okay, here we go...
Click to view attachmentYou have items 1,2 and 6 in your horn setup. Items 4 and 5 are not part of the 74 horn assembly, and items 3 and 7 are for the steering column bearings.
Item 2: This is in your steering column assembly. The ring on the outside provides elecrticity to the horn wire, which is attached. The black tab on the bottom of this is the turn signal canceller.
Item 6: The horn base plate attaches to your horn pad (the part you push to cause the horn to announce). The wire from the ring attaches to the tab on this ring.
Item 1: The horn boot keeps the horn pad away from the steering column. When you push the horn pad, the edge of the base plate makes contact with the steering column, which causes the horn circuit to close, causing the horn to announce. When you let up from the horn pad, the boot pushed the base plate back up and away from the column assembly, and the horn circuit opens, causing the horn to stop announcing.
That's it in a nutshell. Use a multimeter to trace your 12 volts through your column assembly and it should show you where your problem is...
Good luck!
Eric Read