Horn, cruise ctl not working right

This is kind of a strange problem. The horn works with the key off and in the acc. positions, but not in the "on" position. Also the cruise control does not work. The ground wire for the horn and cruise attaches to the hub of the steering wheel and should ground through the steering shaft, "I think". The reason the horn only works in the two mentioned positions is that it grounding throught the wheel lock.

My truck is a '91 F350 with an F250 steering column. It is not a tilt wheel.

My question is, where does the steering shaft ground to the chassis? It seems to me that is the solution. I need some input because I am stuck. Thanks in advance. :)