The switch includes a large column lock that often sticks in the shaft. Try taking pressure off the steering column while playing with the key. THe lock cylinder with the key inside should move outward & allow the lock to turn. Dn't force it or the key WILL break. There's a light spring that is supposed to pop the switch cylinder outboard when you start to turn it. Most switches can be fixed by you once you get the switch out & apart, simply by cleaning the 30-yr-old solidified grease off its innards, re-lubing things and maybe replaceing the spring that often collapses or breaks. You really DON'T want to know what a replacement OEM switch costs....