Depends on year, there are two circuits. The OP's loose wire near the steering box points to earlier type with long wire down the column? This wire from the horn would be in the loom to the column switches on the later circuit (I thought). Though every day's a schoolday.
Some bays have a short bit or wire at the bottom of the column tube that clips to it and goes to the horn... no wires at the top or down the centre
