Takemychance

Problem, truck runs great get up to go to work turn the key and the key just turns like its missing something, not a complete 360 more like 180. feels lose like something not connected I don't think it's the ignition cause lights on dash come on and key turns. What else could it be, I was told to look for the ignition switch lock actuator where would I find that and how would I know if it's broken. Thanks for all your help