Need to replace ignition switch

The spline is likely to be metric on the later car, and the diameter of the hub may not match your column. If the spline matches, and the length of engagement is similar, you should be good to go.

the ignition module (ignition switch on top of the steering column) normally doesn't get stuck.

things you can try:
steering wheel lock: (the pin gets a "burr" on it and locks everything up) wiggle steering wheel back and forth while trying to turn key.

transmission lock (parking on an incline will jam up the interlock)
push the shifter farther into park while trying to turn the key, or wiggle shifter

There is a piece of forged metal that is called a rack that attaches to a rod that gies down to the bottom of the column to the Ignition switch these racks have been known to break and jamb up and I have also seen Ignition switches jamb also. Go to the base of the column and remove the switch and see if the key lock cylinder moves all the way now. Then trace your problem to either a jambed Ignition switch or a bad rack and rod.

you must have dislodged a wiring connector ?? take it all off and check it again

The steering wheel does have to come off to access the ignition lock cylinder, however the ignition switch is mounted to the column and does not require the wheel to be removed. A locksmith would have rekeyed the lock cylinder. The high beam switch is mounted of the left side of the column and is actuated by a 6 inch long rod. This does not require the wheel to come off.

With the key in the on possition. Hook a positive wire from the battery to the starter terminal were switch kicks it in. See if it turns over for you. if so you have a bad switch. if not, a bad starter.

you have to remove the steering wheel then the screw that holds the ignition lock in place. you will nee a steering wheel puller to do this. also there is a small ring that holds the horn assembly and pressure plate on the shaft that you need to remove as well. once you remove these items the phillips head screw that holds the tumbler in must be removed and then the tumbler will come out install is in reverse order

your steering column has a plate with 4 inverted torx fasteners I believe they are e8 fasteners, you must remove the upper tilt flange to gain access to these bolts , a few special tools will be needed : Pivot pin puller , steering wheel puller , lockplate depresser to name 3. the job takes about 1.5 hours to complete. hope this helps a little.

The ignition switch or the ignition tumbler? They are two different things. The tumbler is where you put the key, and the ignition switch is bolted to the bottom of the steering column.

If you are talking about replacing the ignition switch and your truck is equipped with an airbag (in 1995 Chevy trucks had them as standard equipment) you should probably go to an expert for this question. I would take the time to visit the local dealership and just find a mechanic and speak with him for a few minutes, chances are he'd help out.

Usually with airbag situations you are suppose to unplug the battery from the system and then wait xx minutes (I've heard from 15 to 60 minutes) in order to wait for the airbag electronic system to lose power, causing potential accidental deployment.

Lock cylinder & keys is about $90. Switch alone is around $45 with wiring harness. Don't know if switch comes with a new lock cylinder. Thought I had to replace mine, so read up on it in Haynes Repair manual before jumping in. Just did this today. Took my switch apart, cleaned it - nothing wrong, put it back together. Doing that, I didn't have to remove the lock cylinder, so I can't offer hands on with that.
My '89 pickup does not have shearhead bolts as described in the manual - guess some models do. Here's what the book says (with my add-ons):

- Disconnect neg. battery cable
- Remove steering column cover (bottom half - 5 phillips screws)
- Unplug ignition switch wiring harness (I didn't do this - must be back up under the dash somewhere)
- Remove the two ignition switch/steering lock mounting bolts (phillips) If shearhead bolts, cut a slot in the head with a chisel, then use a flat blade screwdriver to remove. You can get to these two screws by turning the steering wheel first one way, then the other. (Once you get in there, you'll see removing it is not a big issue)
- Remove switch assembly from steering column.
- Install is reverse of removal procedure