Steering Column Wiring?

[ChevDog1]

Hey guys - new member here, and I already have a question. My truck is a 1980 C10 Stepside. It has the 250 I6, and was originally equipped with a three speed maual with column shift. I bought the truck from a guy who had lost interest in the project, after he had swapped in a TH400. Part of his trans swap was to get a non-tilt column out of what he said was a Suburban (didn't mention year). The turn signal stalk has been modified - looks to have an aftermarket cruise switch on it.

The trouble I am having is with the wiring. He simply plugged the column harness into the body harness on the truck. I have ignition (I have the truck running now), the headlights work, floor mounted dimmer works, hazard lights work, and the brake lights work. What I don't have is wipers, turn signals, park lights, horn. In addition, when I try to use the wipers, the gauges all go nuts, and both of the turn signal indicators on the dash come on. The truck will also start in gear. Also - he pulled a heavy gauge yellow wire and connected it to a heavy gauge purple wire with a wire nut. If I disconnect this, the starter doesn't work.

I'm guessing that this column must be a later model, but do not know how to tell for sure. Do any of you have experience with a similar issue? Is there a way to modify the wiring on my column to work?

Thanks!