Could be a couple issues.  Could be the switch on the column under the dash that is dirty or your cylinder is worn/dirty.  I would maybe first put some graphite or lube in the cylinder and see if that helps.  If not, maybe pull your steering wheel and drop the column and see if you can see where it is sticking at.  Everything is mechanical the key actuates a rod so that stuff might just need a good cleaning. Good luck to you.