My headlamp switch was around $50 at the dealer.  I think list is somewhere
around $75.  Mine was a '98 Regal so the switch might be different than
yours.  I didn't ohm mine at all when I took it out so I can't offer any
advice on checking yours.  On the Regal, the lights are automatic with DRL.
The headlight switch is dashmounted, not on the column.  Don't know if
that's the same as yours.  I guess about the best I can offer to you is that
the headlight switch is a pretty common failure that results in no dash
lights.

One thing you might try that worked for me to identify my problem is to
whack on the dashboard immediately above the switch while the problem is
occurring.  Or - whack the headlight switch itself.  I could do both and
make my dash lights work until the switch finally got to a point that the
dashlights would never work.  I could also get them to work in the early
failure stages, by twisting the headlight switch in the manner of turning
the  dash light level up and down.  Eventually that too failed to affect the
problem, but it at least point conclusively to the switch.

Hope this helps.