1985 GMC-pick up Truck running lights

GMC Truck

Running Lights:
I just replaced my 1985 steering column with a 1986 steering column. The plugs are exactly the same but my running lights stay on. The headlight switch is mounted on the dash.

With the switch being mounted on the dash, it has nothing to do with the column. Other than the fact that you removed the dash plate to install the column. If you had no issue with the lights remaining on before you worked on it, go back to the dash plate. As it is not properly installed and is not allowing the light switch to be pressed all the way in.