Dash and turn signal issues
Well ask away, we can guide you along. If you think the harness is factory to 68, and has simply had the later column interfaced into it, things should not be too bad to figure out.
Here's some of the stuff you might be up against in the cluster, ALL of which is pretty much repairable, you simply have to get it out and go to it
Harness connector pins on the circuit board: These come loose or break. They can generally be repaired. On my 67, I opted to solder wire pigtails to the pc board traces, and replaced the original connectors with Molex style which I bought at Radio Shack
The socket for the gauge IVR (instrument voltage regulator) is made of brass contact fingers. On mine, not making contact with the board traces, had to solder jumpers across
Build or buy a new IVR. RTE engineering sells them, solid state, and there are others.
The gauge connector nuts may be loose / corroded. Replace with real nuts and tighten / loosen / tighten to scrub the connection clean
The gauge units may or may not be accurate
The instrument lamp sockets may have weak contact fingers, be corroded, burned out bulbs, and corroded / dirty PC board where they twist in. Clean, bend contacts, replace sockets and bulbs as needed.
This is NOT hard to do. Post back as you go. We can offer advice and point you to previous threads. There's a lot of informative guys on here.