the switch is located on the bottom of the steering column in the area of the brake pedal. the actuator is located in the top of the column under the covers you are talking about.
to determine if it is the actuator or not,, reach under the dash and find the ignition switch. it it held to the column by two bolts. if i remember correctly, they have 7/16 wrench heads on them. if you remove the switch, you can use a small screwdriver to work the switch. if you can start the truck with the switch, than the actuator is most likely the problem, and we can direct you to it's replacement.