Most horns work by running power from the fuse box through a relay to the horn to a ground. Another power wire goes to the activating side of the solenoid, up the column to the horn button to ground. When the horn is depressed it sends current to ground thus activating the sloenoid. When the solenoid activates it allows power to go the horn. When you checked your horn you may have checked it on the down stream side of the solenoid. You need to check the activation side to see if solenoid works. If it does you may have a broken wire in the column, especially if it is a tilt wheel. You also mentioned a hot wire. To my knowledge ( I may be wrong) there is no hot wire. As soon as the horn wire hits anything metal. The horn should blow.