How to replace ignition lock tumbler?

The ignition switch need to be replace, because there will be some day when it will stop working and that day could be anytime and anywhere.
Is it c/k series?
IF YES FOLLOW INSTRUCTION BELOW.
IF NO LET ME KNOW WICH ONE YOU HAVE .

Remove the column shroud halves.
Remove the column-to-dash attaching bolts and slowly lower the steering column, making sure that it is supported.
Remove the multi function switch if necessary.
Remove the key alarm switch, if equipped by gently prying the alarm switch retaining clip with a small screwdriver. Rotate the alarm switch 1 / 4 in. turn and remove
Make sure that the switch is in the Lock position. If the lock cylinder is out, pull the switch rod up to the stop, then go down one detent.
Disconnect the actuating rod from the switch.
Remove the two screws and the switch

To install:

Before installation, make sure the switch is in the Lock position.
Attach the actuating rod to the switch.
Install the switch using the original screws. Tighten the screws to 12 inch. lbs. (1.4 Nm).
Install the key alarm switch, if equipped . Make sure the retaining clip is parallel to the lock cylinder. Rotate the alarm switch 1 / 4 in. turn until locked in place.
Install the multi function switch if removed
Replace the column. Tighten the nuts to 22 ft. lbs. (29 Nm); the bolts to 20 ft. lbs. (27 Nm).
Install the column shroud halves.
IF THERE IS ALARM, FOLLOW THIS:
Exploded view of the alarm switch removal

OK, if I understand your issue, you turn the key to start, sometimes the key comes back to the run position and sometimes it doesn't correct? You say you bought a new switch. Which part? The key cylinder (pic A) or the actual ignition switch (pic B)?

If you bought part A, that part needs to be programmed into the system. Otherwise the security system will prevent the engine from starting because you have the wrong key (different from what is programmed into the system)

If you bought part B it won't change the issue either. It only moves with the ignition interlock cam to the position you want. The real issue is inside the mechanical section of the shift interlock in the column. There is a spring that moves the interlock and also lets the key rotate forward/back. It has either corroded or partially broke.

It is possible to replace it BUT it is actually much easier, faster and usually cheaper to replace the steering column itself with a used one. Then you would take your current key cylinder out (part A) and replace the one in the replacement column with it so you don't need to reprogram the security system to a different key.

It would depend on the actual build date and options ordered if it has VATS. The easy way to tell is to look at the key. If it has a chip in it you have VATS. Also look at the dash when you first turn on the key and during the bulb test, if you see a Security light you have a VATS vehicle.
If you don't that just makes it easier to select a replacement column. Or take it to the local mechanic, he could tear the column apart and repair it as he's probably seen the issue before and knows ho to repair it. Your choice on that.

There you go.

Glad to hear you got it fixed thats what we like to hear.

Ignition switch located on the steering column  way down almost above the brake pedal you have a link that connect the switch to a rotating ignition cylinder and key I would suspect a broken ignition switch actuator rod or a bad ignition cylinder

Hello my name is Dave.

First question I have is does it have tilt steering? If it does it's not an uncommon problem for the bolts in the column to come lose and cause the rod that goes from the key switch to the ignition module to get jammed inside the column. If this is the problem the column will have a lot of play in it as it it will rock up and down without releasing the tilt mechanism. I couldn't find a diagram or instructions on repairing this issue so I'll do my best to walk you through the procedure. First step is to remove the steering wheel and turn signal switch. After that you need to remove the pivot pins on the side of the column, there is a special tool to do this but if you look you will see they are threaded inside and I have found that taking a bolt of that thread size and putting through a socket that the pin will fit through and tightening it will pull the pin out easily. After that if you look straight down to the top of the lower portion of the column you will see three inverted torx bolts, I have found that if you take a 8mm or 5/16 6 point 1/4 drive socket you can work it in without removing the upper portion completely, now just simply tighten those bolts and reassemble and make sure the ignition rod that runs down the left side of the column isn't bent and if it is it is usually relatively simple to straighten it. I hope this has been helpful and if there is a different issue please feel free to ask more questions and we will be glad to help you further and thank you for using 2CarPros.

You need to remove the steering wheel to access the ignition switch. Once it is off, you will have access to the switch. Remove steering wheel. Remove plate under steering wheel. Then refer to the pictures below.

Hi Bigmac,

More than likely your ignition switch/cylinder is binding. You can take them apart and clean them but is just as easy to replace it.

Here is another posting with a similar issue. Please review this and the attached documents and let me know if you have questions. Thanks

https://www.2carpros.com/questions/chevrolet-silverado-ignition-switch-wont-turn-off-stuck-in-on-position