I have a problem with my 72 GMC that I just bought as a daily driver. When I move the column shift up and down the lights flicker and radio cuts out. Tried disconnecting all wiring from column such as reverse, start switch, signals no luck. Trans linkage is not touching wires either, don't get it, is there a plug that I'm missing, I also unpluged gear indicator light. PLEASE HELP ME.

Try disconnecting the horn relay. I had a busted horn wire shorting in the column on my 70 and it did some pretty strange stuff until I disconnected it. May be something else but it's worth a shot.

On the bottom side of the column, there is a thin piece of sheet metal that clips on. Pop that off and sinspect the wires. You may have to unbolt the column to get it off, I can't recall at the moment.

Make sure you have some good grounds, One from block to Firewall, One from Block to Frame, One from frame to Cab, nose to frame. You can never have to many grounds. Regular wires do not work for ground wires, use ground straps.